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PLAGUE 


PLAGUE 

ITS  CAUSE  AND  THE  MANNER  OF  ITS 
EXTENSION— ITS  MENACE— ITS  CONTROL  AND 
SUPPRESSION— ITS  DIAGNOSIS  AND  TREATMENT 


BY 

THOMAS  WRIGHT  JACKSON,  M.D. 

MEMBER   AMBHICAN    RED    CROSS    SANITARY    COMMISSION    TO    SERBIA,    IQIS;     LATBLT 

CAPTAIN  AND   ASSISTANT  SURGEON,   V.    S.    VOLUNTEERS;   LATELY  LECTURER  ON 

TROPICAL  DISEASES,  JEFFERSON  MEDICAL  COLLEGE;   MEMBER    OF    MANILA 

MEDICAL  SOCIETY  AND   PHILIPPINE   ISLANDS  MEDICAL  ASSOCIATION; 

AUTHOR  OF  A   TEXT  BOOK   ON  TROPICAL  MEDICINE;  DIRECTOR, 

DEPARTMENT    OF     SANITATION    AND    EPIDEMIOLOGY 

FOR  H.  E.  MULFORD    COMPANY 


WITH  BACTERIOLOGIC  OBSERVATIONS 

BY 

DR.  OTTO  SCHOBL 

BUREAU  OF  SCIENCE,  MANILA 


ILLUSTRATED 


PRESS  OF 

J   B.  LIPPINCOTT  COMPANY 


COPYBIGHT,  1916 
BY  THOMAS  WRIGHT  JACKSON,  M.D. 


THIS   BOOK  IS  DEDICATED   BY   THE  AUTHOR   TO 

DR.  ALDO  CASTELLANI 

REGIUS  PROFESSOR  OF  TROPICAL  DISEASES, 
TOSriVEBSITY  OF  NAPLES.  EMINENT  IN  MEDICAL 
RESEARCH,  MY  FRIEND,  COLLEAGUE  AND  COM- 
RADE    DURING     STRENUOUS    DAYS     IN    SERBIA 


CONTENTS 

PAGE 

Introduction 11 

CHAPTER  I 

Its  History  and  Its  Extension 19 

History  of  Plague — The  Widespread  Dissemination  of  Plague 
in  Recent  Years — The  Appearance  of  Plague  in  Porto  Rico, 
New  Orleans  and  Manila. 

CHAPTER  II 

The  Cause  and  the  Menace  of  Plague 28 

Causation  of  the  Disease  and  its  Mode  of  Conveyance — 
Types  of  Plague — Chronic  Plague  and  Immunity  in  Rats 
— Flea  Conveyance  of  Plague  Bacilli — The  Stability  of  Viru- 
lence of  Plague  Bacilli — Summary  of  Facts  Concerning  the 
Cause  and  Manner  of  Extension  of  Plague. 

CHAPTER  III 

Its  Control  and  Suppression 40 

Plague  Prevention  by  Extermination  of  Rats — General  Use- 
lessness  of  the  Rat  and  Its  Enormous  Destructiveness,  with 
Details  of  Trapping  and  Other  Extermination  Methods — The 
Manila  Epidemic,  1912-1914 — The  First  Cases — Unusual 
Character  of  Plague  Cases  at  Quarantine — Clinical  Descrip- 
tion of  Two  Cases  at  Quarantine — Inauguration  of  the  Manila 
Epidemic — Directed  to  Take  Charge  of  Plague  Suppression  in 
Manila — Plague  Fighting  Organization — Method  of  Rat  Proof- 
ing and  Rat  Destruction — Correspondence  Between  Dr.  Jack- 
son and  Dr.  Heiser,  Director  of  Public  Health — Observations 
on  Fleas  and  Their  Habits — Conditions  of  Habitations  iii 
Manila  Favoring  Rat  Multiplication  and  Spread  of  Plague — 
Comparative  Statistics  on  Methods  of  Catching  Rats — The 
Natural  Enemies  of  the  Flea — Zoologic  Classification  of  Rats — 
A  Collection  of  Notes  Concerning  Rat  Runs,  Rat  Nests,  Multi- 

5 


6  CONTENTS 

pie  House  Infections  and  Other  Data — Sample  of  Detailed 
Orders  Issued  Regarding  Rat  Extermination — Method  of  Pro- 
cedure of  Collecting  and  Forwarding  Rats  Suspected  of  Plague 
Infection  to  Laboratory — Memoranda  in  Plague  Cases — Letter 
of  Warning  and  Appeal  for  Cooperation — Bacteriologic  Ob- 
servations made  During  the  Manila  Plague  Epidemic,  By  Dr. 
Otto  Schobl — Notes  Concerning  the  Bubonic  Plague  in  Hong 
Kong,  by  Dr.  David  Roberg. 

CHAPTER  IV 

Its  Diagnosis  and  Treatment 165 

Biologic  Diagnosis — Necessity  for  Trained  Bacteriologist — 
Bacteriologic  Procedure — Non-Biologic  Diagnosis — Sympto- 
matology— Pathologic  Considerations — Treatment,  Conditions 
and  Prognosis — Serum  Treatment — Symptomatic  Treatment 
— Statistical  Studies  in  Mortality — Dosage  and  Technique  of 
Serum  Administration — Prophylactic  Serum  and  Anaphylaxis 
— Plague  Vaccines. 


ILLUSTRATIONS 

PAGE 

Rat-Proof  STRtrcTUEE 48 

Cleaning  and  Rat-Peoofing  in  Basement 69 

Bamboo  Hotjse  Supports  not  Sealed  with  Cement 86 

Materials  Must  be  Moved  About  in  the  Search  for  Rats 93 

A  Rat-Infested  Plague  Interior 95 

Progressive  Post-mortem  Changes  in  Rat  Cadavers 105 

Plague  House 116 

Bamboo  House  Supports  Sealed  with  Cement 119 

View  of  House  Where  Infected  Rats  Were  Found 120 

Animal  House 144 


PLAGUE 


ITS  CAUSE  AND  THE  MANNER  OF 
ITS  EXTENSION  — ITS  MENACE  — ITS 
CONTROL  AND  SUPPRESSION 
—  ITS    DIAGNOSIS  AND    TREATMENT 


INTRODUCTION 

The  question  of  the  need  for  new  books  upon 
medical  topics  must  ever  remain  undecided,  by  gen- 
eral agreement,  in  the  medical  profession. 

There  is  no  such  thing  in  medical  literature  as 
an  insistent  demand  from  the  profession  for  new 
volumes  upon  old  topics. 

Authors  need  not  hope,  therefore,  to  create  the 
impression  that  they  are  meeting  long-felt  though 
unexpressed  wants  of  medical  readers  in  launching 
new  books. 

On  the  other  hand,  the  creator  of  a  new  volume 
upon  an  old  subject  should  seek  justification  for 
literary  paternity  in  the  progressive  changes  in  the 
status  of  our  knowledge  of  disease,  its  causes,  pre- 
vention, and  cure.  Such  changes  are  admittedly 
going  on  with  a  certain  degree  of  constancy  and  at 
such  a  rate  of  frequency  that  new  presentations  of 
old  themes  are  both  justified  and  desirable  from 
time  to  time. 

With  this  idea  in  mind  and  with  the  desire  to 

present,  in  useful  and  practical  form,  a  work  which 

shall  contain  at  least  some  unhackneyed  material 

11 


12  PLAGUE 

and  which  shall  represent  modern  studies  and  a 
record  of  actual  control  work  done  in  this  justly- 
dreaded  disease,  the  following  pages  are  submitted  to 
the  medical  profession  and  to  sanitarians  generally. 

With  a  profound  respect  for  the  laboratory 
worker  and  his  work  and  with  a  profound  convic- 
tion that  to  him  belongs  the  greater  measure  of 
credit  for  real  accomplisliment  in  connection  with 
plague  up  to  the  present  time,  I  desire  to  insist  that 
the  true  utility  of  knowledge  gained  within  labo- 
ratory walls  lies  in  its  intelligent  application  in  the 
outer  world  and  that  ofttimes  this  application  must 
be  made  by  men  who  are  themselves  without  ex- 
tended laboratory  training.  An  appreciation  of 
principles — with  an  intelligent  ability  to  accept,  to 
appropriate,  to  apply  and,  most  of  all,  to  refrain 
from  entering  without  due  preparation  the  domain 
of  the  laboratory  worker — is  an  indispensable  req- 
uisite in  the  equipment  of  the  practical  sanitarian, 
upon  whom  must  fall  the  responsibilities  of  success 
or  failure  in  combating  the  disease  we  are  now  to 
consider. 

During  the  past  fourteen  years  it  has  been  my 
privilege  to  observe  two  epidemics  of  plague  in  the 
PhilijDpine  Islands.  Some  of  these  observations  were 


INTRODUCTION  13 

made  in  the  capacity  of  a  military  medical  officer,  but 
my  later  observations,  upon  which  this  report  and 
study  are  chiefly  based,  were  made  from  the  view- 
point of  a  civil  health  officer.  At  different  times  I 
have  been  called  upon  to  deal  with  the  disease  both 
as  sanitary  officer  and  clinician,  and  from  October, 
1912,  to  July,  1914, 1  had  charge  of  all  plague  sup- 
pressive measures  in  Manila.  In  1914  I  was  also 
in  charge,  as  acting  chief,  of  the  San  Lazaro  Hos- 
pitals Division  of  the  Bureau  of  Health,  Manila, 
where  all  cases  of  plague  are  brought,  either  for 
treatment  or  autopsy. 

As  some  of  the  material  which  I  have  collected 
for  text-book  articles  during  the  past  eight  years 
bears  directly  upon  the  present  discussion  and  pres- 
entation, I  have  ventured  to  quote  from  it,  some- 
times without  rephrasing,  such  parts  as  are  accurate 
at  the  present  time.  I  am  also  quoting  freely  from 
the  records  and  from  the  experiences  of  my  pred- 
ecessors and  colleagues  in  the  work  in  Manila. 

It  should  be  understood  that  the  pathology  of 
the  disease  has  been  practically  omitted  from  con- 
sideration as  out  of  place  in  an  epidemiologic  in- 
vestigation and  report.  The  pathologic  side  of  the 
work  during  the  Manila  epidemic  of  1912-1914  was 


14  PLAGUE 

covered  in  a  masterly  manner  by  Dr.  B.  C.  Crowell 
and  his  associates  at  the  Medical  School  of  the  Uni- 
versity of  the  Philippines,  and  I  have  no  doubt  that 
the  record  of  the  work  done  and  studies  made  will 
appear  in  appropriate  form  in  due  time  and  will 
hereafter  be  referred  to  as  among  the  most  valuable 
pathologic  studies  ever  made  during  a  plague 
epidemic,  on  account  of  their  accuracy  and  com- 
pleteness. 

I  have  included,  as  of  great  value  and  directly 
related  to  the  epidemiologic  phase  of  this  study, 
reports  of  some  of  the  bacteriologic  work  done  in 
connection  with  this  epidemic  at  the  Bureau  of 
Science,  Manila,  by  Dr.  Otto  Schobl.  I  am  sure 
that  the  value  of  his  studies  as  reported  in  part  here, 
with  his  permission,  will  be  apparent  to  every  care- 
ful reader.  I  am  greatly  indebted  to  him  for  his 
permission  to  make  use  of  this  portion  of  his  studies. 
Having  been  in  daily  touch  with  Dr.  Schobl  during 
the  year  and  a  half  of  the  continuance  of  this 
epidemic,  I  can  appreciate  to  the  fullest  extent  the 
painstaking  and  accurate  character  of  his  work  and 
findings,  of  which  the  part  here  presented  is  by  no 
means  the  greatest. 

I  am  quite  aware  of  the  fact  that  there  are  those 


INTRODUCTION  15 

who  view  with  some  question  the  practicabihty  of 
controning  plague  by  the  measures  apphed  in 
Manila,  as  recited  here;  but  American  plague 
workers  are  likely  to  meet  this  unbelief  by  pointing 
to  the  accomplished  fact,  in  San  Francisco,  in  Hono- 
lulu, in  Porto  Rico,  as  well  as  in  Manila;  and  be- 
fore long,  as  we  confidently  expect,  in  New  Orleans. 
These  exponents  of  the  school  which  contends 
that  plague  epidemics  are  little  affected  by  rat-ex- 
cluding, rat-destroying  and  rat-proofing  efforts,  be- 
lieve that  the  waning  and  disappearance  of  epidemic 
plague  in  a  given  place  depend  in  chief  part  upon 
the  exhaustion  of  susceptible  material  among  the 
rodent  population.  However  appealing  this  argu- 
ment may  be,  it  is  impossible  for  its  exponents  to 
duplicate  American  results  with  equal  results  in  the 
cities  of  China,  India,  Java  and  elsewhere,  where 
governmental  control  and  adequate  financial  ability 
to  carry  out  campaigns  have  been  lacking,  from 
one  cause  or  another.  Wherever  our  methods  have 
been  followed,  at  home  and  in  the  insular  possessions 
of  the  United  States,  we  have  terminated  human 
epidemics  of  plague  and  have  apparently  put  an 
end  to  rat  plague  in  comparatively  short  cam- 
paigns.   So  long  as  this  discrepancy  in  results  con- 


16  PLAGUE 

tinues  we  shall  favor  the  American  plan.  Whe 
we  review  the  work  and  results  of  Blue  and  his  fe 
lows  of  the  United  States  Health  Service  and  tl 
officers  of  the  Bui-eau  of  Health  of  the  Pliilippir 
Islands,  we  find  little  reason  for  us  to  favor  a  chan^ 
to  the  expectant  plan  of  waiting  for  an  epidemic  1 
run  its  course. 

While  speaking  of  the  Philippine  Islands,  tl 
admirable  work  of  Strong  in  ]Manila,  covering  yea: 
of  study  of  the  immunity  problem,  and  his  dange 
ous  and  higlily  valuable  work  as  a  member  of  tl 
Commission  wliich  studied  the  Manchurian  epidem 
of  pneumonic  plague  in  1911,  must  be  mentione( 

Some  years  ago  I  called  attention  to  the  fai 
that  few,  if  any,  American  cities  were  prepared  1 
meet  an  outbreak  of  plague  with  an  adequate  supp] 
of  antipest  serum  and  that  the  preparation  of  ant 
plague  serum  was  a  neglected  or  overlooked  branc 
of  serum  manufacture  in  the  United  States.  Sin( 
that  time,  in  the  midst  of  a  plague  epidemic  i 
IManila,  where,  for  a  time,  the  supply  of  locally  pr^ 
pared  (Bureau  of  Science)  serum  threatened  1 
become  exhausted,  I  looked  into  the  possibilities  ( 
getting  a  supply  elsewhere  and  found  that,  to  do  s 
in  anything  like  a  reasonable  length  of  time,  wi 


INTRODUCTION  17 

impossible.  Fortunately  the  threatened  serum 
famine  did  not  occur,  the  local  supply  in  Manila 
proving  adequate,  although  for  a  few  weeks  we  were 
obliged  to  make  use  of  a  stock  of  Japanese  serum 
which  had  been  on  hand  for  several  years.  Since 
the  warning  of  some  years  ago,  at  which  time  the 
plague  danger  was  an  anticipated  one,  bubonic 
plague  has  actually  appeared  in  the  United  States 
(New  Orleans),  the  cases  being  sufficiently  numer- 
ous to  cause  grave  concern  and  to  call  forth  the 
utmost  repressive  efforts  of  the  authorities.  The 
possibility  of  plague  appearance  in  the  coast  cities 
of  the  United  States,  at  any  time,  cannot  be  disre- 
garded and  provision  for  the  treatment  of  human 
cases,  as  well  as  repressive  (antirat)  measures,  is 
imperative.  Antiplague  serum  is  not  producible 
upon  a  few  hours'  notice,  nor  is  it  manufactured  in 
the  United  States.  In  view  of  present  war  con- 
ditions the  difficulty  of  securing  serum  from  over- 
seas sources  is  greatly  increased,  so  that  we  are  well- 
nigh  compelled  to  depend  upon  home-produced 
serum.  In  view  of  the  uselessness  of  drug  treat- 
ment it  is  plainly  the  duty  of  national,  state  and 
municipal  authorities  to  keep  on  hand  a  reasonable 

supply  of  antipest  serum  to  meet  any  outbreak. 
2 


18  PLAGUE 

Manufacturers  of  biological  products  realize  that 
the  preparations  for  producing,  storing  and  market- 
ing antiplague  serum  are  expensive  and  that  the 
maintenance  of  immunized  animals  and  the  employ- 
ment of  expert  serologists  call  for  expenditures 
which  are  unlikely  to  be  recovered  from  any  demand 
for  serum  and  that,  moreover,  the  government  is 
doing  and  will  do  all  that  lies  within  its  power  to 
make  the  serum  unnecessary,  by  excluding  plague. 
These  are  not  encouraging  conditions  to  lead  Amer- 
ican serum  producers  to  add  antiplague  serum  to 
the  list  of  their  products.  If,  under  these  adverse 
conditions,  any  producer  of  biologic  products  shall 
undertake  to  produce  and  maintain  an  adequate 
supply  of  antiplague  serum,  he  will  merit  credit  for 
a  truly  philanthropic  service  and  will  deserve  the 
support  of  governments,  national,  state  and  munici- 
pal, as  well  as  that  of  the  medical  profession. 


CHAPTER  I 

ITS  HISTORY  AND  ITS  EXTENSION 

In  plague  there  exists  the  most  intimate  relation- 
ship between  cause  and  prevention.  We  will  there- 
fore set  forth  here,  as  briefly  and  concisely  as  their 
importance  will  permit,  the  principal  facts  related 
to  the  causation  of  the  disease.  Without  an  under- 
standing of  this  relationship  there  can  be  no  rational 
preventive  treatment. 

These  facts  constitute  one  of  the  interesting 
stories  of  modern  medicine :  the  story  of  the  arrange- 
ment and  interpretation  of  certain  apparently  un- 
related facts,  some  of  them  long  known  to  men,  in 
the  clear  light  of  modern  method;  the  story  of  the 
application  of  analysis,  synthesis,  logic  and  experi- 
ment, all  leading  to  the  creation  of  an  understand- 
ing which  permits  us  to  battle  successfully  with 
pestis  bubonica,  one  of  the  most  ancient  of  human 
plagues. 

History. — This  disease  has  an  historic  interest, 
most  engaging  and  fascinating,  which  one  finds  it 
difficult  to  pass  over  with  mere  mention. 

I  venture  to  recall,  therefore,  that  plague  almost 

19 


20  PLAGUE 

certainly  dates  back  to  the  pre-Christian  era,  the 
earlier  record  naturally  being  lacking  in  sufficient 
accuracy  of  description  to  enable  us  to  identify  the 
recorded  epidemics,  definitely  and  positively,  with 
true  bubonic  plague. 

An  epidemic  of  the  second  century  B.C.,  as  de- 
scribed, seems  to  have  been  one  of  true  plague,  while 
the  pandemic  which  began  in  Egypt  in  the  sixth 
century  a.d.,  thence  extending  to  Constantinople, 
Europe  and  the  British  Isles,  was  certainly  the  dis- 
ease known  in  modern  times  as  the  plague.  This 
pandemic,  beginning  as  the  plague  of  Justinian,  was 
probably  followed  by  the  continuous  presence  of  the 
disease  in  Europe,  marked  by  many  local  outbreaks 
and  periods  of  quiescence  and  extending  down 
through  the  centuries  to  the  period  of  the  Crusades. 
In  the  eleventh  and  twelfth  centuries  the  returning 
Crusaders  spread  the  plague  widely  through 
Europe,  which  country  it  ravished  from  the  eleventh 
to  the  fourteenth  centuries,  reaching  its  climax  of 
intensity  in  the  "  Black  Death  "  of  Europe  of  the 
Middle  Ages.  The  disease  thereafter  continued  to 
devastate  Europe,  the  great  population  centres, 
Paris  and  London,  suffering  especially  from  its 
visitations  and  its  more  or  less  constant  presence. 


ITS^HISTORY  AND  ITS  EXTENSION       21 

The  Great  Plague  of  London,  the  last  important 
epidemic  of  the  disease  in  that  metropolis,  began  in 
1664  and  lasted  five  years.  With  less  than  half  a 
million  of  inhabitants  it  is  estimated  that  London 
gave  one  of  every  six  or  seven  of  her  citizens  to  the 
Black  Death  during  the  first  year  of  the  epidemic. 
Then  followed  a  remarkable  disappearance  of  the 
disease  from  Western  Europe.  The  eighteenth 
century  was  marked  by  few  epidemic  appearances 
of  plague. 

At  the  end  of  the  first  half  of  the  nineteenth 
century  it  had  practically  disappeared  from  Egypt 
and  from  European  and  Asiatic  Turkey,  formerly 
its  favorite  haunts.  In  interior  Asia  it  has  probably 
existed  for  centuries,  the  non-emigrating  character 
of  the  people  limiting  and  confining  its  devastations. 

To  these  centres  and  to  the  commercial  invasion 
of  China,  we  must  probably  trace  the  beginning  of 
the  present  pandemic  of  plague,  which  exists  to-day, 
a  menace  to  the  civilized  and  uncivilized  world.  In 
the  days  of  the  Crusades  a  religious  invasion  of  the 
infected  centres  caused  the  disease  to  spread 
throughout  Christendom,  while  in  the  present  day  a 
commercial  invasion  has  caused  it  to  spread  com- 
pletely around  the  world. 


22  PLAGUE 

That  this  is  a  truth  and  not  a  fanciful  statement 
is  shown  by  the  appearance  of  plague  in  the  follow- 
ing countries  since  1894,  when  it  spread  from  in- 
terior China.  In  every  case  it  has  followed  those 
sanitary  lines  of  least  resistance,  the  paths  of 
commerce. 

Extension. — To  the  eastward,  from  China,  it 
spread  to  Japan,  the  Philippines,  Australia,  the 
Hawaiian  Islands,  Alaska,  California,  Mexico, 
Peru  and  the  western  coast  of  South  America.  To 
the  westward,  it  invaded  India,  Mauritius,  Egypt, 
Suez  ports.  Eastern,  Central  and  South  Africa, 
Mediterranean  ports.  Great  Britain  ( Scotland) ,  the 
West  Indies  and  Brazil.  In  the  last  twenty  years 
plague  has  caused  millions  of  deaths,  and,  during  a 
single  week  in  April,  1907,  it  destroyed  more  than 
75,000  lives  in  India,  a  number  about  equal  to  the 
deaths  of  a  year  in  London  during  the  Great  Plague 
of  1665.  In  contrast  with  India  the  rest  of  the 
world  has  suffered  little  during  the  present  world- 
epidemic,  but  this  loss,  while  relatively  small,  is 
enormous  when  translated  into  lives  and  dollars. 
The  figures  for  India  are  simply  huge. 

Mortality. — The  official  lists  of  deaths  in  India 
for  the  last  twenty  years  include  some  in  which  the 


ITS  HISTORY  AND  ITS  EXTENSION      23 

number  of  reported  deaths  per  year  exceeded  one 
million,  and  it  has  been  estimated  that  the  actual 
number  of  persons  dead  from  the  plague  during 
this  period  approximates  8,000,000. 

It  is  gratifying  to  note  a  marked  decrease  in  the 
total  mortality  in  the  reports  of  the  last  few  years, 
but  so  long  as  the  annual  death  list,  year  after  year, 
was  measured  by  hundreds  of  thousands,  rather 
than  thousands,  the  situation  could  not  be  consid- 
ered as  anything  but  grave. 

Widespread  Dissemination  in  Recent  Years. 
— Without  going  into  statistics  deeply  we  may  con- 
sider also  the  list  of  countries,  states  and  islands 
from  which  plague  cases  have  been  reported 
officially  during  the  last  few  years. 

My  purpose  is  to  invite  attention  to  the  con- 
tinued existence  of  various  plague  foci,  any  one  of 
which  might  serve  to  extend  the  infection  further, 
were  governmental  quarantine  and  public  health 
supervision  relaxed. 

During  August,  September,  October,  Novem- 
ber and  December,  1909,  plague  cases  occurred  in 
India,  Mauritius,  China,  Japan,  Egypt,  Turkey, 
Russia,  British  East  Africa,  the  Azores,  Venezuela, 


24  PLAGUE 

Ecuador,  Peru,  Chili,  California  (two  cases),  and 
the  Hawaiian  Islands. 

During  the  first  half  of  1910  no  very  marked 
variation  in  the  distribution  of  plague  occurred, 
cases  being  reported  from  practically  all  of  the 
foreign  countries  just  named. 

A  year  later  the  situation,  so  far  as  the  distribu- 
tion of  plague  cases  is  concerned,  was  not  greatly 
changed,  as  may  be  seen  from  the  following  tabu- 
lation, which  I  have  abstracted  from  the  British 
Medical  Journal  of  September  16,  1911. 

India. — Deaths  from  plague  in  India  during  the 
first  six  months,  604,634.  Most  prevalent  (1) 
United  Provinces,  281,317;  (2)  Punjab,  171,084; 
(3)  Bengal,  58,515;  (4)  Bombay  Presidency, 
28,109.    Deaths  in  July,  not  included  above,  8990. 

Hong  Kong. — April  24  to  August  21,  255  cases, 
194  deaths. 

China. — Since  January  1,  1911,  plague  was  re- 
ported in  varying  intensity  in  (provinces  and 
towns)  Manchuria,  Peking,  Tien-tsin,  Chefo,  Shan- 
tung, Shanghai,  Amoy,  Foochow,  Swatow,  Canton, 
Pakhoi  and  Laichow. 

Indo-China. — At  Saigon,  in  March  and  April, 
1911,  many  cases  reported.     April  17  to  May  7, 


ITS  HISTORY  AND  ITS  EXTENSION       25 

56  cases;  17  deaths.  May  22  to  May  28,  37  cases; 
12  deaths. 

Siam. — In  Bangkok  plague  was  more  severe 
during  1911  than  in  any  previous  year.  March  15 
to  April  15,  33  cases  and  29  deaths. 

Java  and  Sumatra. — In  Java,  May  25  to  June  3, 
105  cases  and  62  deaths  (one  province).  In 
Sumatra  plague  was  present,  no  statistics. 

Straits  Settlements. — A  few  cases,  mostly  im- 
ported, reported  in  1911. 

Japan. — ^A  few  cases  at  Kobe  in  1911.  In  For- 
mosa, from  April  2  to  April  15,  31  cases;  24  deaths. 

Egypt. — ^Plague  reported  from  Port  Said, 
Suakin  (on  board  ship),  Cairo  and  Alexandria; 
also  from  11  provinces.  The  province  of  Kena  had 
a  severe  outbreak,  May  5  to  May  31,  51  cases  and 
49  deaths. 

Persia. — Several  cases  reported  from  ports  on 
the  Persian  Gulf.  ' 

Turkey  in  Asia. — A  few  cases  at  Muscat,  Basra 
and  at  Port  of  Jeddah. 

British  East  Africa. — Kismayu  and  Port 
Florence  reported  a  few  cases  in  April,  1911. 

Mauritius. — January  1  to  April  11,  110  cases 
and  70  deaths. 


26  PLAGUE 

Portuguese  East  Africa. — Plague  was  reported 
present  at  Nahoria  in  May,  1911. 

Russia. — In  the  Kirgis  Steppe  in  the  Astrakan 
Government  in  January,  50  cases ;  30  deaths. 

South  America. — Plague  prevailed  during  1911 
in  Peru,  Ecuador,  Brazil,  Chile  and  Venezuela.  No 
severe  outbreak  except  in  Peru,  where  from  Feb- 
ruary to  May  many  cases  occurred  and  died.  At 
Libertad,  in  March,  were  reported  60  cases  and 
23  deaths. 

Appearance  of  Plague  in  Porto  Rico,  New 
Orleans  AND  Manila. — The  developments  of  1912, 
which  most  concern  us,  were  the  appearance  of 
human  plague  and  the  discovery  of  plague-infected 
rats  in  Porto  Rico,  Cuba,  and  the  Philippines,  and 
the  discovery  of  infected  rats  in  New  Orleans.  Thus 
the  Atlantic  cities  of  the  United  States  were  for 
the  first  time  seriously  threatened,  and  the  menace 
of  the  pestilence  at  home  loomed  up  on  our  horizon 
with  sufficient  prominence  to  excite  public  concern. 
Our  protectors  and  guardians  of  the  United  States 
Public  Health  Sei^ice,  to  whose  watchfulness  we 
must  credit  our  prolonged  escape  from  the  plague, 
are  carrying  out  all  the  protective  measures  at  their 
command  with  the  utmost  activity. 


ITS  HISTORY  AND  ITS  EXTENSION      27 

At  the  present  time  we  find  Porto  Rico  freed 
from  the  disease.  New  Orleans  has  undergone  and 
is  still  undergoing  treatment  which  may  be  expected, 
most  confidently,  to  clear  it  of  both  human  and 
animal  plague. 

Of  Manila  and  the  work  there,  much  will  be 
found  in  the  following  pages,  but  as  both  rat  plague 
and  human  plague  have  been  absent  for  more  than 
a  year  we  may  fairly  look  upon  the  epidemic  as 
ended.  After  so  long  an  interval  as  this  any  re- 
appearance of  plague  may  fairly  be  viewed  as  a 
new  epidemic,  although  it  is  not  humanly  possible 
to  say  that  rat  plague  has  entirely  and  permanently 
disappeared  from  the  city  of  Manila,  as  yet. 


CHAPTER  II 

THE  CAUSE  AND  THE  MENACE  OF  PLAGUE 

The  foregoing  facts  are  quite  sufficient  to  make 
us  realize  both  the  possibihty  and  the  danger  of  a 
world- epidemic ;  a  danger  which  has  existed  for 
some  years  and  which  recently  has  been  especially 
menacing  to  the  United  States. 

Causation  of  the  Disease. — ^Plague  is  an  acute 
infectious  epizootic  disease,  caused  solely  by  Bacillus 
pestiSj  a  bacterial  organism.  The  disease  is  com- 
mon to  man  and  to  a  number  of  the  lower  animals 
and  fowls. 

Prominent  among  the  animals  susceptible  to 
the  disease  is  the  rat,  and  from  this  animal,  through 
the  intermediation  of  the  flea,  bj^  far  the  most  cases 
of  human  plague  arise.  In  California  the  ground 
squirrel  (Citellus  heecheyi) ,  a  rodent  closely  related 
to  the  marmots  of  Asia,  plays  a  similar  role.  Of 
the  Asian  marmots,  the  tarbagan,  a  large  rodent, 
also  commonly  suffers  from  subacute  chronic 
plague,  which  is  transmissible  to  man  as  an  acute 
disease  by  the  fleas  which  the  animal  harbors. 

Its    Conveyance. — Although    conveyance    of 

28 


THE  CAUSE  AND  MENACE  OF  PLAGUE  29 

plague  through  rats  by  contact  alone — that  is  to  say 
without  the  medium  of  the  flea — is  denied  by  mod- 
ern experimenters,  it  is  perhaps  wiser  and  safer 
to  consider  the  disease  infectious,  inoculable  and 
contagious  in  the  common  medical  meaning  of  these 
terms.  While  it  is  usually  conveyed  to  man  by 
the  flea,  it  may  be  acquired  by  the  inhalation  of 
plague  bacilli  and,  according  to  some  authorities, 
by  ingesting  or  swallowing  the  bacilli. 

When  infection  takes  place  through  the  diges- 
tive tract,  or  in  other  words,  by  the  ingestion  of 
bacilli,  either  the  flesh  of  plague-infected  animals 
or  fowls,  or  food  superficially  contaminated  with 
plague  bacilli  by  rats,  cockroaches  or  other  carriers, 
serves  as  the  medium. 

Speaking  practically,  the  possibility  of  infection 
through  ingestion  is  nearly  negligible.  Indeed,  the 
conclusion  of  Simpson  in  regard  to  this  possibility 
has  been  disputed  and  denied.  However,  the  recent 
occurrence  of  plague  in  a  cat  in  Manila,  in  my  own 
experience,  observed  with  me  and  carefully  worked 
out  by  Dr.  Otto  Schobl,  points  strongly  to  the  pos- 
sibihty  of  ingestion  plague,  the  cat  in  this  case  ap- 
parently having  acquired  plague  from  eating  rats 
dead  from  plague. 


30  PLAGUE 

A  full  account  of  this  case  appears  in  the  bac- 
teriologic  observations  of  Dr.  Schobl  and  in  my 
recital  of  the  history  of  the  Manila  epidemic. 

Types  of  Plague. — Plague  in  man  may  be  of 
several  types  and  these  are  designated  by  names 
descriptive  of  the  symptoms  or  of  the  regions  of 
the  body  most  affected.  Thus  we  have  bubonic, 
septicemic  and  pneumonic  types.  As  both  mild 
and  virulent  cases  occur,  we  also  use  terms  descrip- 
tive of  the  severity  and  course  of  the  cases.  Thus 
we  describe  certain  cases  as  ambulant,  abortive, 
larval  and  fulminant.  In  the  rat  the  evidences  of 
plague  are  less  striking  in  life  than  they  are  at  the 
post-mortem  table.  Indeed  plague-stricken  rats, 
either  naturally  or  artificially  (experimentally)  in- 
fected, often  show  very  slight  evidences  of  disease 
before  death.  Chronic  plague  in  rats  and  a  relative 
immunity  to  inoculation  in  certain  wild  rats  are 
fairly  well  recognized  phenomena. 

Flea  Conveyance  of  Plague  Bacilli. — Both 
male  and  female  fleas  convey  plague,  but  the  exact 
method  of  carrying  the  plague  bacilli  from  diseased 
rats  to  man,  while  fairly  well  determined,  is  of  such 
recent  decision  as  to  leave  room  for  further  experi- 
mentation.   At  present  it  is  believed  that  the  flea 


THE  CAUSE  AND  MENACE  OF  PLAGUE  31 

deposits  plague  bacilli,  at  the  time  of  biting,  upon 
the  skin,  by  ejecting  the  contents  of  its  rectum 
and  by  regurgitation  of  its  stomach  contents.  At 
least  the  flea  is  known  to  perform  these  acts  at  the 
time  of  biting,  and  the  rubbing  or  scratching  of  the 
flea  bite  with  the  hand  may  easily  introduce  the 
bacilli  into  the  skin  at  this  spot/ 

The  possibility  that  the  flea  introduces  the 
plague  bacilli  upon  his  mandibles,  or  the  skin-pierc- 
ing armament  with  which  he  is  provided,  is  also  to 
be  considered.  However,  the  following  facts  sup- 
port the  first  proposition.  It  has  been  experi- 
mentally shown  that  the  average  capacity  of  a  flea's 
stomach  is  about  one-half  of  a  cubic  millimetre  and 
that  thousands  of  plague  bacilli  may  be  ingested 
by  the  flea  during  the  biting  of  a  plague-diseased 
rat;  that  the  plague  bacilli  multiply  enormously 
and  for  many  days  in  the  flea's  stomach  and  that 

*  Acknowledgment  is  hereby  made  to  the  Contributors  to 
"  The  Rat  and  Its  Relation  to  Public  Health  "  by  various 
authors,  prepared  by  direction  of  the  Surgeon-General,  P.  H. 
and  M.  H.  S.,  for  numerous  facts  utilized  in  the  preparation 
of  this  article.  The  particular  contributors  whose  valuable 
chapters  have  been  drawn  upon  for  information  are  D.  E. 
Lantz,  C.  W.  McCoy,  D.  H.  Currie,  Carrol  Fox,  Rupert  Blue, 
W.  C.  Rucker,  R.  H.  Creel,  M.  J.  Rosenau,  V.  C.  Heiser, 
W.  C.  Hobdy,  and  J.  W.  Kerr. 


32  PLAGUE 

the  bacilli  are  found  only  in  the  insect's  digestive 
tract ;  that  plague  bacilli  are  regurgitated  from  the 
stomach  and  are  voided  from  the  rectum  with  the 
digested  blood. 

It  has  also  been  proved  that  almost  all  varieties 
of  rat  fleas,  under  favorable  circumstances,  will  bite 
man  and  that  the  most  common  human  flea  {Puleoc 
irritans)  is  frequently  found  upon  rats,  the  flea, 
generally  speaking,  being  much  less  particular  in 
his  choice  of  hosts  and  in  his  permanence  of  resi- 
dence than  most  insects  and  ectoparasites  in  general. 

Of  the  rat  fleas,  Pulex  pallidus  (Loemopsylla 
cheopis)  is  common  under  various  names  in  India, 
the  Phihppines,  Austraha,  Italy,  Brazil  and  in 
tropical  countries  generally.  It  bites  both  rat  and 
man.  Ceratophyllus  fasciatus,  the  common  rat  flea 
of  Great  Britain  and  the  United  States,  also  bites 
both  rat  and  man.  In  North  America  and  else- 
where certain  other  fleas  of  the  genus  Ceratophyllus 
have  been  found  upon  ground  squirrels,  cats,  rats, 
sparrows  and  in  chicken  yards. 

Dog  fleas  and  cat  fleas  (genus  Ctenocephalus) 
also  infest  rats,  and  fleas  of  other  genera  are  found 
upon  mice,  rats  and  ground  squirrels  rather  indis- 
criminately. 


THE  CAUSE  AND  MENACE  OF  PLAGUE  S3 

The  significance  of  these  facts  in  connection 
with  prevention  of  plague  is  apparent  and  it  is 
plain  that  our  warfare  against  fleas  must  be  made 
upon  all  fleas  and  not  upon  a  single  variety.  In 
this  connection  the  possibilities  of  the  conveyance 
of  plague  bacilli  by  other  suctorial  parasites  and  by 
insects  which  are  not  parasites,  must  be  borne  in 
mind. 

Thus  the  bed-bug,  the  louse,  the  tick  and  the 
mosquito  must  be  suspected  as  possible  intermedi- 
aries and  the  fly  and  the  cockroach  as  possible  food 
contaminators.  Indeed,  laboratory  experiments 
have  already  incriminated  bed-bugs,  flies  and  lice 
as  potential  vectors  of  plague  bacilli. 

Experiment  and  observation  have  demonstrated, 
however,  that  above  all  other  parasites  and  in- 
sects, the  flea  is  most  likely  to  convey  the  plague 
germ  from  rat  to  man,  by  reason  of  his  frequent 
excursions  from  rat-host  to  human-host,  his  taste 
for  blood  from  either  host,  his  enormous  activity 
and  his  ability  to  jump.  After  a  searching  inquiry 
into  the  plague  question  the  Indian  Plague  Com- 
mission came  to  the  conclusion  that  contagion  plays 
a  very  minor  part  in  the  spread  of  the  disease,  less 
than  three  per  cent  of  human  cases  being  so  acquired. 


34  PLAGUE 

This  commission  also  decided  that  infection  is 
conveyed  from  rat  to  rat  and  from  rat  to  man 
solely  through  the  agency  of  fleas.  While  these 
conclusions  are  probably  true — and  therefore  of  the 
utmost  importance  from  the  standpoint  of  prac- 
tical prevention — I  should  question  whether  the 
other  possibilities,  however  remote,  are  entirely 
negligible. 

Seasonal  conditions  may  affect  the  course  of 
an  epidemic  in  various  ways,  (a)  By  effect  upon 
flea  prevalence,  cold  weather  greatly  lessening  the 
number  of  insects,  (b)  By  effect  upon  rats,  cold 
weather  and  rains  either  driving  them  from  over- 
ground to  underground,  or  vice  versa,  or  from  their 
principal  avenues  of  travel  in  cities  (the  sewers), 
into  houses  and  buildings,  (c)  By  effect  upon 
the  plague  germ.  Bacillus  pestis.  The  resistance  of 
this  organism  is  very  variable,  sunlight  and  drying 
being  its  greatest  enemies,  while  darkness  and  damp- 
ness are  its  chief  allies.  So  far  as  temperature  is 
concerned,  the  plague  bacillus  is  not  likely  to  be  seri- 
ously affected  by  natural  temperatures,  as  it  is 
not  destroyed  by  heat  below  150  degrees  Fahren- 


THE  CAUSE  AND  MENACE  OF  PLAGUE  35 

heit,  nor  by  cold  measured  by  zero  Fahrenheit,  which 
means  that  it  survives  freezing,  generally  speaking. 

It  is  probable  that  the  periods  of  greatest  sea- 
sonal prevalence  of  plague  will  be  found  to  corre- 
spond generally  with  increased  prevalence  of  rat 
fleas.  During  the  periods  when  rat  fleas  are  absent 
or  least  prevalent,  the  disease  is  perpetuated  in  the 
form  of  chi'onic  (subacute)  rat  plague  in  a  small 
number  of  the  rodents.  The  India  Plague  Com- 
mission made  and  verified  this  observation. 

Cholera  epidemics  often  abate  spontaneously 
and  this  is  believed  to  be  due  in  part  to  attenuations 
of  virulence  and  changes  in  the  cholera  organism 
which  may  be  demonstrated  in  the  laboratory.  We 
can  hardly  hope  for  such  spontaneous  abatements  in 
plague  epidemics,  as  it  has  been  found  difficult  to 
attenuate  or  to  intensify  cultures  of  plague  bacilli 
permanently  in  laboratory  experiments  with 
animals.  If  it  is  true  that  plague  epidemics  are 
often  marked  by  a  preponderance  of  mild  cases 
in  the  early  days  and  a  gradual  subsidence  of  in- 
tensity of  the  cases  as  the  epidemics  wane,  we  prob- 
ably will  have  to  look  to  the  susceptibility  of  our 


36  PLAGUE 

patients  for  our  explanation  of  this  phenomenon, 
rather  than  to  variations  in  the  virulence  of  the 
plague  bacilli.  If  plague  bacilli  continue  to  be 
distributed  to  susceptible  people  the  disease  should 
continue  with  a  general  stability  of  virulence. 
Stability  of  Yirulexce  of  B.  Pestis. — ^Ac- 
cording to  Strong,  stabihty  of  virulence  is  a  marked 
characteristic  of  B.  pestis,  it  having  been  shown  by 
him  that  it  is  difficult  to  increase  the  virulence  of  a 
very  virulent  strain  or  to  intensify''  an  attenuated 
one  in  laboratory  animals,  working  with  monkeys, 
rats  and  guinea-pigs.^  If  his  observations  are  cor- 
rect (and  they  seem  to  correspond  with  the  find- 
ings of  other  observers),  the  oft-recorded  occur- 
rence of  a  preponderance  of  mild  cases  of  plague 
in  the  early  days  of  an  epidemic  and  the  gradual 
subsidence  in  intensity  of  the  disease  as  the  epidemic 
approaches  its  close  will  have  to  be  explained  upon 
other  grounds  than  those  of  variability  of  virulence 
by  attenuation  of  virulent  strains  alone.    While  he 

^"Studies  in  Plague  Immunity,"  R.  P.  Strong,  Philippines 
Journal  of  Science,  June  1907,  No.  3.  Frequent  reference  has 
been  made  to  these  studies  in  the  preparation  of  this  article, 
for  which  acknowledgment  is  hereby  made. 


THE  CAUSE  AND  MENACE  OF  PLAGUE  37 

admits  that  B.  pestis  may  become  attenuated  under 
certain  conditions  many  times  during  the  course 
of  an  epidemic,  it  may  also  regain  its  virulence, 
he  contends,  under  other  conditions. 

With  these  facts  concerning  the  cause  and  the 
manner  of  extension  of  plague  and  its  menace  be- 
fore us,  we  are  in  position  to  approach  the  problem 
of  prevention  intelligently,  and  in  the  case  of  plague 
prevention  is  preeminently  preferable  to  cure,  as 
well  as  decidedly  more  practicable. 

I  think  we  may  be  permitted  here  to  sum  up 
the  problem  of  plague  prevention  thus:  Without 
fleas,  without  rats,  or  without  human  plague  cases, 
there  can  be  no  extension  of  plague,  practically 
speaking. 

Therefore  the  destruction  of  both  rats  and  fleas, 
the  isolation  of  human  plague  cases,  and  the  ex- 
clusion from  them  of  all  suctorial  parasites  and  in- 
sects, will  provide  practical  security  for  mankind 
generally. 

A  word  concerning  pneumonic  plague  may  be 
permissible.  This  form  of  plague  occasionally  oc- 
curs in  epidemics  of  great  fatality,  as,  for  example, 
the  epidemic  in  Manchuria,  North  China,  u  few 
years  ago. 


38  PLAGUE 

The  mystery  of  this  outbreak  was  largely  dis- 
pelled by  the  work  of  the  Americans,  Strong, 
Teague  and  Barber,  of  the  Bureau  of  Science  of 
Manila. 

The  occurrence  of  secondary  pneumonia  in 
bubonic  or  septicsemic  plague  is  rather  common  and 
it  is  likely  that  such  secondary  plague  pnemnonias 
are  the  starting  points  of  epidemics  of  pneumonic 
plague,  i.e. J  of  cases  of  primary  plague  pneumonia, 
the  point  of  infection  being  in  the  respiratory  organs 
and  the  infection  being  acquired  through  the  inspira- 
tion of  plague  bacilli. 

The  principal  prerequisites  seem  to  be  an  ex- 
tremely moist  atmosphere  under  confined  conditions 
and  a  low  temperature ;  conditions  most  unfavorable 
to  evaporation  and  ventilation.  Under  these  con- 
ditions the  pneumonic  patient  sprays  plague  bacilli 
into  the  air  while  coughing  and  droplet  infection 
follows. 

It  is  therefore  apparent  that  epidemic  pneu- 
monic plague  is  controllable  by  sanitary  and  hy- 
gienic measures  and,  furthermore,  that  in  the  ab- 
sence of  original  cases  of  bubonic  and  septicemic 


THE  CAUSE  AND  MENACE  OF  PLAGUE   39 

plague,  with  secondary  plague  pneumonias  which 
give  rise  to  primary  plague  pneumonia  in  the  man- 
ner explained,  respiratory  plague  in  epidemic  forai 
will  not  occur. 

There  is  no  evidence  pointing  to  the  conveyance 
of  respiratory  plague  by  insects  or  other  carriers. 


CHAPTER  III 

ITS  CONTROL  AND  SUPPRESSION 

Plague  Prevention. — At  present  the  most 
promising  and  the  most  rationally  based  phase  of 
plague  control  is  that  of  prevention.  The  reason 
for  this  is  plainly  apparent.  If  the  facts  in  the 
case  are  as  stated  and  if  the  conclusions  of  the 
Plague  Commissioners  and  students  of  epidemi- 
ology the  world  over  are  correct,  to  eradicate  plague 
we  need  only  to  control  its  carriers. 

To  exterminate  the  rat  (and  perhaps  the  mar- 
mot and  ground  squirrel),  to  prevent  the  transpor- 
tation of  rats  or  of  infected  rat  fleas  in  ships,  trains, 
clothing,  merchandise  and  upon  the  bodies  of  men 
and  animals  from  the  numerous  foci  or  plague 
centres  of  the  world  to  non-infected  localities,  is  a 
beautiful  plan  indeed. 

Restricted  to  single  communities,  even  where 
the  intelligence,  patriotism,  effort  and  wealth  of 
the  whole  people  are  enlisted,  the  undertaking  is 
formidable,  with  obstacles  to  its  execution,  and  dis- 
couragement must  often  be  expected.  Extended 
in  its  application  to  the  whole  plague-infected  world 

40 


ITS  CONTROL  AND  SUPPRESSION        41 

it  becomes  an  undertaking  seemingly  impossible  of 
accomplishment. 

Yet  we  are  encouraged  to  face  the  situation  by 
a  glance  at  what  has  been  accomplished.  The 
United  States,  perhaps,  presents  the  highest  ex- 
amples of  achievement  in  the  cases  of  San  Fran- 
cisco and  Manila.  The  work  in  San  Francisco  is 
too  recent  and  has  been  too  well  published  to  require 
detailed  review  here.  A  successful  campaign  against 
rats  in  1907  practically  terminated  an  epidemic  of 
considerable  proportions  well  within  a  year.  Be- 
hind this  movement,  however,  were  the  powerful 
machinery  of  the  Federal  Government,  money  in 
generous  amount  and  a  considerably  aroused  pub- 
lic, resentful  of  the  mismanagement  of  the  1903 
epidemic,  whereby,  through  pure  fear  of  financial 
loss  to  commercial  interests  and  by  a  disgi-aceful 
suppression  of  the  truth,  California  was  made,  per- 
manently perhaps,  one  of  the  world's  plague  centres. 

It  has  been  estimated  that  the  rat  population  of 
the  world  is  equal  to  the  human  population,  and  this 
estimate  does  not  appear  to  be  unreasonable  when 
one  considers  as  indices  the  destruction  of  the  ro- 
dents in  cities  by  the  hundreds  of  thousands,  upon 


42  PLAGUE 

single  farais  by  the  thousand,  and  the  wonderful 
procreative  powers  of  the  rat. 

Economic  Importance  of  Rat  Destruction. 
— It  is  certain  that  the  economic  importance  of  rat 
destiniction  upon  groimds  other  than  those  purely 
sanitary  must  be  impressed  upon  the  pubhc  wher- 
ever a  rat  campaign  is  to  be  carried  on. 

The  absolute  inutility  of  the  rat,  its  enormous 
destructiveness  to  crops,  to  merchandise  in  ware- 
houses and  in  transit,  to  poultry,  eggs,  fruits  and 
vegetables,  to  buildings  and  furniture,  and  its  in- 
cendiary habits  causing  annual  fire  losses  of  con- 
siderable magnitude,  must  be  emphasized  in  season 
and  out  of  season.  Such  items  as  the  value  of  the 
grain  consumed  by  a  single  rat  per  year,  as  estimated 
by  the  experts  of  the  Agricultural  Department,  are 
convincing  arguments  in  the  case.  At  a  daily  con- 
sumption of  two  ounces,  the  ration  for  a  full-gi'own 
rat,  this  grain  value  varies  from  sixty  cents  per 
year,  for  wheat,  to  two  dollars  per  year,  for  oat- 
meal, for  each  rat  subsisted.  Similar  data  in  great 
variety,  relating  to  direct  and  indirect  losses,  are 
available  for  the  purpose  of  making  impressive  the 
economic  need  for  rat  destruction. 

Accumulated  experience  from  various  countries 
and  cities  shows  plainly  that  there  is  no  single 


ITS  CONTROL  AND  SUPPRESSION        43 

method  of  rat  destruction  to  be  depended  upon  to 
the  exclusion  of  all  others  and  it  also  shows  that 
without  governmental  direction  and  supervision, 
backed  by  ample  authority  and  the  ability  and  will- 
ingness to  expend  considerable  money,  neither 
single  nor  combined  methods  will  be  successful. 
Moreover  in  the  countries  where  special  effort  is 
most  needed  there  is  often  distrust  on  the  part  of 
the  natives,  religious  prejudice  against  the  destruc- 
tion of  animal  life  and  frequently  open  opposition 
to  the  authorities  in  their  efforts  to  destroy  rats. 
The  same  superstitions  and  religious  beliefs  which 
prevent  the  killing  of  venomous  snakes  in  India, 
at  the  annual  cost  of  thousands  of  human  lives, 
operate  against  most  measures  of  rat  destruction 
proposed  by  the  Government. 

Extermination  Methods. — The  plans  and 
weapons  of  warfare  against  rats  include  the  use 
of  poisons ;  traps ;  starvation ;  rat-proof  construction 
of  buildings,  wharves,  bakeries,  stables,  granaries, 
etc.;  the  introduction  of  diseases  among  the  rat 
population  by  bacterial  viruses  and  the  conservation 
of  the  natural  enemies  of  the  rat,  such  as  the  cat, 
the  dog,  the  ferret,  the  mongoose,  and  certain  wild 
animals  and  birds  of  the  woods  and  fields. 


44  PLAGUE 

Among  the  most  widely  used  and  most  eiFec- 
tive  poisons  is  arsenous  acid  boiled  with  rice,  or 
mixed  with  cheese  or  cornmeal  in  the  form  of  a 
paste,  or  placed  upon  sweets  and  fruits. 

Crude  phosphorus  is  chiefly  used  in  similar 
pastes.  When  mixed  with  glucose  its  inflammable 
properties  are  said  to  be  lost.  Its  inflammabihty  is, 
of  course,  a  serious  obstacle  to  its  general  use. 

Strychnine,  owing  to  its  bitter  taste,  is  of  little 
value  in  poisoning  rats,  and  when  used  is  best  com- 
bined with  glucose  and  one  per  cent,  of  cyanide  of 
potassium.  Soaked  v/heat,  bread  or  similar  food 
is  then  treated  with  this  mixture  and  placed  where 
rats  may  eat  it.  It  is  said  to  be  eaten  readily  by 
ground  squirrels  with  fatal  effect.  It  is,  however, 
expensive  and  apt  to  be  taken  by  domestic  fowls. 
Most  rat  poisons  have  the  disadvantage  of  being 
dangerous  to  human  life  and  must  be  used  with 
caution  wherever  children  and  ignorant  native  per- 
sons are  about. 

Trapping. — Trapping  has  been  found  to  be  a 
very  effective  means  of  rat  destruction  in  cities. 
(See  later  pages  for  relative  efficiency  of  traps.) 
Rat  traps  are  of  several  varieties  and  are  con- 
structed upon  various  principles.    It  is  sometimes 


ITS  CONTROL  AND  SUPPRESSION        45 

desirable  to  catch  the  rats  alive  and  uninjured,  and 
for  this  purpose  barrel  traps,  wire  cage  traps  and 
similar  devices  are  placed  in  the  rat  highways.  These 
highways  are  readily  discovered  in  the  cities.  Con- 
siderable care  must  be  taken  to  overcome  the  natural 
caution  of  the  rat,  and  this  includes  judgment  in 
the  use  of  attractive  bait,  the  concealing  and  smok- 
ing of  traps  after  handling  and  perhaps  the  use 
of  some  scent,  such  as  the  oil  of  anise,  of  which  rats 
seem  to  be  fond.  As  a  general  rule  bait  should 
differ  from  the  food  naturally  supplied  by  the 
locality.  For  example,  about  granaries  and  stables 
fresh  animal  food  should  be  used  for  bait,  while 
about  slaughter  houses,  meat-markets,  fish-markets 
and  similar  places,  where  animal  ofFal  is  abundant, 
the  rat  should  be  tempted  with  vegetable  bait. 

Where  the  circumstances  will  permit,  and  this 
is  apt  to  be  so  for  ground-squirrel  destruction,  the 
burrows  may  be  filled  with  some  asphyxiating  or 
poisonous  gas.  In  this  manner  whole  families  of 
rodents,  and  their  fleas  as  well,  are  destroyed. 

The  system  is  not  often  applicable  in  houses,  but 
aboard  ships  it  is  found  most  effective,  the  holds  of 
ships  being  flooded  with  sulphur  dioxide,  developed 
by  burning  sulphur  in  a  special  furnace  provided 


46  PLAGUE 

with  a  pumping  and  piping  system  for  delivering 
the  gas  at  distant  parts  of  the  ship.  In  empty  ships' 
holds  and  elsewhere  the  simple  burning  of  sulphur 
in  open  vessels  effects  the  same  results,  provided 
sufficient  sulphur  and  a  sufficient  nmnber  of  vessels 
be  used  and  further  provided  that  the  generation 
and  confining  of  gas  be  sufficiently  prolonged.  In 
San  Francisco  harbor,  where  for  more  than  a  year 
nine  vessels  were  disinfected  per  day,  this  method 
was  adopted  as  more  effective,  speedy  and  econom- 
ical than  any  other  system.  It  has  the  disadvan- 
tage, in  the  case  of  laden  ships,  of  affording  some 
danger  of  fire. 

Carbon  bisulphide  has  been  extensively  used  in 
California  in  the  burrows  of  ground  squirrels.  Its 
fumes,  being  heavier  than  air,  penetrate  the  bur- 
rows and  promptly  poison  or  asphyxiate  all  living 
animals  and  fleas.  Absorbent  material  of  some  kind 
is  saturated  with  the  liquid  and  placed  in  the  en- 
trance of  the  burrow,  which  is  then  quickly  sealed  to 
confine  the  gas. 

It  will  be  seen  that,  in  common  with  other 
methods  of  rat  destruction,  fumigation  has  a  limited 
application  and  a  number  of  serious  objections.  It 
is  particularly  useful  aboard  ships. 


ITS  CONTROL  AND  SUPPRESSION        47 

The  method  should  never  be  employed  by  mi- 
skilled  persons  or  those  unacquainted  with  the 
dangers  to  human  life  from  noxious  or  asphyxiating 
gases. 

Starving  Rats. — The  subjects  of  the  starva- 
tion of  rats  and  rat-proof  construction  may  be  con- 
sidered together. 

Just  as  the  pig  in  the  Philippine  Islands  and 
elsewhere  in  the  Orient  must  give  place  as  a  scav- 
enger of  human  excreta  to  modern  and  decent 
methods  of  waste  disposal,  so  must  the  rat,  a  gar- 
bage scavenger  the  world  over,  give  place  to  sys- 
tematic garbage  collection  and  removal,  with  tem- 
porary storage  of  garbage  in  covered  metal  cans 
(rat  proof). 

Incidentally  it  may  be  mentioned  that  the  effect 
of  such  measures  upon  the  prevalence  of  flies  and 
the  transmission  of  disease  by  these  insects  will  be 
very  great  and  very  beneficial  to  the  public  health. 

Food  must  be  kept  from  rats  and  rats  must  be 
kept  from  the  food.  Perhaps  the  greatest  resorts 
of  rats  are  the  places  where  cattle  are  fed,  where 
grain  is  stored  and  where  animals  are  killed. 
Slaughter  houses,  markets,  grocery  stores,  restau- 
rants, bakeries,  wharves  and  warehouses  must  be 


48  PLAGUE 

regulated  by  ordinances  duly  enforced.  Much  can 
be  done  with  screens  of  heavy  iron  wire  with  a  mesh 
of  less  than  one  inch. 

When  concrete  and  metal  have  displaced  wood 
and  plaster  as  construction  materials;  when  plank 
sidewalks  and  refuse  piles  are  no  more  and  when  the 
catch  basins  of  sewers  have  been  made  rat-proof 
the  subsistence  problem  for  the  rat  will  be  greatly 
increased  in  difficulty,  and  starvation  should  then 
begin  to  lessen  the  rat  population,  at  least  in  the 
cities. 

Rat-proofing. — Municipal  authorities  should 
take  up  the  matter  of  rat-proof  construction  for  new 
buildings  and  the  rat-proofing  of  old  ones  by  ap- 
proved alterations.  In  Manila,  Hong  Kong  and 
elsewhere  these  methods  are  receiving  attention  and 
encouraging  reports  are  recorded,  more  particularly 
with  regard  to  the  disappearance  of  plague  in  dis- 
tricts so  treated  than  in  the  disappearance  of  rats. 
This  is  most  important,  for  if  the  rat  and  his  fleas 
are  excluded  from  houses  and  therefore  from  in- 
timate association  with  man  ( an  apparently  feasible 
matter  through  the  rat-proof  construction  of  build- 
ings), protection  against  human  plague  is  in  great 
measure  accomplished. 


ITS  CONTROL  AND  SUPPRESSION        49 

In  Manila  the  disappearance  and  continued  ab- 
sence of  human  plague  in  previously  infected  local- 
ities goes  hand  in  hand  with  the  introduction  of 
systematic  rat-proofing  in  sections  where  cases  of 
human  plague  occur. 

These  measures  were  first  instituted  in  1906  and 
plague  disappeared  from  Manila  in  the  same  year 
and  did  not  reappear  until  1912. 

From  1900  to  1905,  $15,000  was  paid  in  rat 
bounties  and  $325,000  was  paid  for  salaries,  wages 
and  expenses  in  rat  catching,  with  little  appreciable 
effect  upon  the  number  of  rats  and  without  causing 
the  plague  to  entirely  disappear.  It  must  be  ad- 
mitted, however,  that  practical  control  of  the  dis- 
ease was  attained  during  this  period. 

Rat-proofing  of  dwelling  houses  is  less  expensive 
than  perpetual  wholesale  rat  destruction  and  is  a 
perfectly  effective  measure  against  human  plague. 
In  the  suppression  of  the  San  Francisco  epidemic 
in  1907  rat-proofing  was  also  extensively  resorted  to. 

The  expense  of  rat-proofing  has  been  generally 
considered  as  prohibitive,  but  if  the  work  be  con- 
fined at  first  to  the  vicinity  of  infected  centres  and 
if  it  be  carried  on  subsequent  to  rat-destruction  in 
corresponding  areas  the  expense  need  not  always  be 


50  PLAGUE 

prohibitive — at  least  in  American  governed  cities. 
The  Manila  plan  of  plotting  the  city  into  "plague- 
infected  "  areas  corresponding  with  the  capture  of 
plague-diseased  rats  and  systematically  working 
within  geographic  boundaries  in  which  rat  plague 
exists  or  is  likely  to  spread,  as  determined  by  rat 
captures  and  examinations  of  the  rats  for  signs  of 
plague,  has  proved  to  be  a  good  plan. 

To  prevent  the  transportation  of  rats  in  ships, 
trains  and  merchandise  is  an  undertaking  of  diffi- 
culty as  well  as  of  importance.  In  the  case  of  ves- 
sels it  involves  an  understanding  of  the  manner  by 
which  rats  gain  ingress  to  the  ship  and  the  ways  of 
preventing  them  from  entering.  Few  facts  are  bet- 
ter known,  perhaps,  than  the  fact  that  all  ships  har- 
bor rats,  but,  except  to  the  initiated,  the  extent  to 
which  some  ships  are  infested  is  by  no  means  under- 
stood. I  have  made  voyages  upon  steamships,  which 
upon  alternate  trips  carried  forage  for  animals  in 
the  holds,  when  the  conditions  were,  to  say  the  least, 
uncomfortable.  To  have  one's  state-room  taken 
possession  of  by  rats,  his  clothing  carried  away,  or 
to  awake  with  a  rat  in  his  berth  are  unpleasant,  but 
not  uncommon,  experiences.  I  personally  know  of 
a  woman,  prostrated  with  sea-sickness,  who  was 


ITS  CONTROL  AND  SUPPRESSION        51 

obliged  to  remain  in  her  berth  and  see  four  large 
rats  disport  themselves  about  her  room,  and  in 
another  case,  on  the  same  ship,  a  rat  jumped  from 
the  washstand  into  the  berth  of  a  sleeping  woman, 
running  across  her  exposed  face  and  arm. 

In  travelling  upon  small  dirty  steamers  in  the 
Orient  I  have  often  slept  on  deck,  quite  as  much  to 
avoid  the  rats  and  vermin  in  the  state-rooms  as  for 
better  ventilation.  In  a  certain  ship  in  which  I 
travelled  some  of  the  ship's  officers  amused  them- 
selves by  shooting  rats  with  an  air-rifle  in  the  lower 
decks,  quietly  hiding  themselves  in  dimly-lighted 
places  and  shooting  the  rats  as  they  crossed  the 
hghter  spaces. 

In  many  ships  the  rat  population  far  exceeds 
the  human  population.  In  San  Francisco  310  rats 
were  destroyed  by  a  single  fumigation  on  a  vessel 
of  only  260  tons  burden.  In  Bombay  1300  rats 
were  destroyed  at  one  time  upon  a  single  ship  and 
in  London  1700  were  secured  at  one  fumigation. 

The  ease  with  which  rats  adapt  themselves  to 
new  environment  is  shown  by  the  fact  that  they  live, 
when  permitted  to  do  so,  in  cold  storage  and  re- 
frigerating rooms  where  they  grow  heavy  coats  of 
fur  for  protection  against  the  cold. 


52  PLAGUE 

They  gain  ingress  to  ships  in  three  principal 
ways:  (1)  By  coming  overside  upon  gang-planks, 
wharf  stringers,  etc.  (2)  By  passing  along  the 
lines  by  which  the  ship  is  made  fast  to  the  dock, 
through  hawse  holes,  the  rat  being  an  expert  rope 
walker.     (3)  By  coming  aboard  in  the  cargo. 

By  the  latter  method  rats  are  often  brought 
aboard  by  whole  families,  their  fleas  included.  Many 
styles  of  packages  such  as  barrels,  bales,  crated 
goods,  grain  in  sacks  and  matting  in  rolls  present 
the  rat  with  abundant  opportunity  to  take  pas- 
sage and  it  is  probably  thus,  as  stowaways,  that 
rats  go  to  sea  in  the  largest  number.  Plainly,  then, 
the  placing  of  rat-funnels  upon  all  lines  from  ship 
to  wharf,  the  use  of  special  fenders,  the  raising  of 
gang-planks  and  even  anchorage  in  the  stream  will 
not  prevent  rats  from  getting  aboard  ships  unless 
cargo  disinfection  be  practised  before  loading  the 
vessel.  The  ship  itself  should  be  fumigated  every 
three  months  if  possible. 

Rats  are  doubtless  carried  in  considerable  num- 
bers upon  railway  cars,  both  freight  and  passenger. 

While  riding  in  a  street  car  in  Manila  in  1908 
I  saw  a  rat  run  along  the  window  ledge,  to  the 
mingled  fright  and  amusement  of  the  passengers. 


ITS  CONTROL  AND  SUPPRESSION        53 

The  same  principles  which  apply  in  the  case  of 
ships  apply  to  cars  and  trains  as  well.  Grain  cars 
in  particular  should  receive  especial  attention. 

Rat  Destruction  by  the  Spread  of  Rat  Dis- 
eases.— The  proposal  to  destroy  rats  by  wholesale, 
by  spreading  epizootic  diseases  among  them,  through 
feeding  them  bacterial  virus,  has  received  much  at- 
tention in  the  last  ten  years.  In  1900  Danysz  iso- 
lated a  bacillus  from  field  mice  suffering  an  epi- 
demic disease  communicable  to  rats,  and  great  hopes 
were  entertained  that  by  means  of  this  method  de- 
cided reductions  in  the  rat  population  would  result. 
Indeed  the  results  in  Cape  Town,  South  Africa,  in 
1901,  and  in  Odessa,  Russia,  in  1902,  seemed  to 
justify  the  hope  to  some  extent  and  certain  observers 
still  believe  the  method  to  be  effective.  Experience 
with  the  Danysz  and  other  organisms  has  shown, 
however,  that  introduced  epidemic  diseases  do  not 
destroy  rats  in  sufficient  number  to  do  much  good 
and  that  nearly  all  the  viruses  experimented  with 
are  more  or  less  unreliable. 

Most  of  the  organisms  are  apparently  related 
to  the  colon,  typhoid  or  hog-cholera  groups.  The 
mouse-typhoid  bacillus  {B.  typhi  murium)  was 
originally  isolated  by  Loeffler  in  1899.    The  para- 


54  PLAGUE 

typhoid  bacillus  and  Gartner's  B.  enteritidis  cot- 
respond  closely  with  the  Danysz  organism  and  can 
scarcely  be  separated  culturally.  In  rodents  they 
produce  enteritis,  sometimes  hemorrhagic  in  char- 
acter, and  they  are  by  no  means  to  be  regarded  as 
harmless  for  man,  as  originally  supposed.  In  Japan, 
in  particular,  serious  and  fatal  cases  of  diarrhoeal 
disease  have  followed  the  accidental  eating  by  man 
of  food  treated  by  these  bacterial  poisons. 

On  account  of  the  natural  resistance  of  rats  to 
diseases  of  bacterial  causation  (plague  being  the 
most  notable  exception  to  this  rule),  and  the  clin- 
ical fact  that  no  sufficient  death  rate  among  rodents 
is  produced  by  feeding  them  upon  bacterial  viruses, 
as  well  as  on  account  of  the  dangers  to  man  just 
mentioned,  this  method  of  rat  destruction  is  not  in 
favor  at  present. 

Poisoning  rats  and  ground  squirrels  by  chem- 
ical poisons  seems  to  be  a  preferable  method,  at 
least  equally  effective  and  without  most  of  the  dis- 
advantages of  uncertainty  and  danger  which  attach 
to  the  bacterial  viruses. 

Rat  Destruction  by  Domestic  Animals. — 
Concerning  the  utility  of  such  domestic  animals  as 
are  natural  enemies  of  the  rat,  in  the  warfare  against 


ITS  CONTROL  AND  SUPPRESSION        55 

the  offending  rodents,  there  is  considerable  differ- 
ence of  opinion,  based  upon  varying  experiences. 
I  leave  out  of  consideration  all  but  the  cat  and  dog. 

It  will  be  found  that  wherever  cats  and  dogs 
are  well  housed  (indoors)  and  well  fed  they  are 
apt  to  be  fat,  lazy  and  inefficient.  House  cats  of 
this  class  will  catch  mice  but  will  often  leave  rats 
alone,  but  half -wild  cats,  obliged  to  forage  for  their 
own  subsistence,  are  often  excellent  rat-catchers. 
Small,  active  dogs,  particularly  of  the  terrier  breeds, 
will  often  keep  houses  practically  free  from  rats 
and  upon  farms  they  are  especially  valuable,  par- 
ticularly if  the  construction  of  buildings  is  such  as 
to  permit  them  to  get  beneath  the  floors.  The  em- 
ployment of  these  animals  will  necessarily  be  con- 
fined to  individuals  for  the  freeing  of  individual 
premises  from  rats. 

A  fact  to  be  borne  in  mind  is  one  abeady  cited, 
viz. :  that  cats  and  dogs  sometimes  harbor  the  same 
fleas  as  the  rat.  Infected  rat-fleas  often  leave  dead 
rats  for  other  animals  and,  all  things  considered, 
there  are  many  other  objections  to  the  intimate 
house  dog  and  house  cat  which  find  comfortable 
resting  places  impartially  upon  the  beds  of  adults 
or  the  cribs  of  babies  and  children. 


56  PLAGUE 

Furthermore,  my  personal  observations  have 
been  such  as  to  cause  me  to  place  small  reliance  in 
the  value  of  the  ordinary  dogs  and  cats  found  about 
habitations  wherein  the  construction  is  favorable  to 
rat-harboring. 

Summary  of  Prevention  for  the  Com- 
munity.— Before  passing  to  the  consideration  of 
other  matters  I  would  smn  up  the  measures  of  pre- 
ventive treatment  for  the  community.  There  must 
be  (1)  Active  warfare  against  rats  and  other 
plague-affected  rodents  and  their  fleas;  (2)  Modi- 
fied quarantine — detention  or  disinfection  applied 
to  persons,  goods  and  animals;  (3)  Disinfection  of 
cargoes  shipped  from  infected  ports;  (4)  Isolation 
of  the  sick  and  proper  disposal  of  the  dead;  (5)  In- 
ternational notification  between  governments  of  the 
occurrence  of  plague  within  their  respective  terri- 
tories; (6)  Lastly, — but  we  might  say  fii'st  in  im- 
portance,— the  early  recognition  of  the  presence 
of  plague  and  the  rapid  diagnosis  in  individual 
cases,  both  of  which  are  dependent  upon  laboratory 
workers. 

All  of  these  measures  must  be  fostered,  directed 
and  aided  in  every  possible  way  by  competent  au- 
thority (national  if  possible),  whose  ofiicers  must 


ITS  CONTROL  AND  SUPPRESSION        57 

be  men  of  great  moral  courage  and  of  unselfish  pur- 
pose. Behind  all  of  this  must  be  generous  financial 
support. 

I  can  best  emphasize  the  importance  of  the  ob- 
servance of  the  principles  I  have  laid  down  by  in- 
troducing personal  experiences  in  the  conduct  of 
the  antiplague  campaign  in  Manila  during  1912, 

1913  and  1914. 

I  therefore  present  here  the  following  account 
of  the  epidemic,  the  campaign  of  suppression  and 
the  various  lessons  learned. 

It  should  not  be  difficult  for  the  reader  to  make 
applications  of  the  principles  already  set  forth  and 
to  confirm  by  the  reported  facts  the  assertion  that 
methods  based  upon  these  principles  are  effective. 

If  repetitions  of  any  of  the  foregoing  principles 
occur  it  is  hoped  that,  when  taken  in  connection  with 
concrete  applications  cited,  they  will  not  appear  as 
redundant. 

The  Manila  Epidemic  of  1912  to  1914. — The 
chronologic  facts  concerning  the  development  and 
extension  of  plague  in  Manila  in  1912,  1913  and 

1914  are  as  follows: 

The  disease  made  its  reappearance  in  Manila, 
after  an  absence  of  six  years  for  the  human  disease 


58  PLAGUE 

and  five  years  for  rodent  plague,  two  verified  human 
cases  having  been  recorded  in  June,  1912. 

Preceding  the  appearance  of  the  first  Manila 
cases  there  occurred  upon  incoming  ships  a  number 
of  cases  of  plague  during  the  Spring  of  1912,  de- 
tected at  quarantine.  Although  there  is  no  con- 
clusive evidence  which  connects  these  imported  cases, 
originating  in  Hong  Kong,  China,  with  the  epi- 
demic which  broke  out  in  Manila  a  few  months 
later,  the  fact  of  their  occurrence  and  recognition  is 
interesting  enough  for  us  to  consider  before  taking 
up  the  study  of  the  Manila  epidemic.  Concerning 
these  imported  cases  Dr.  Victor  G.  Heiser,  then 
Director  of  Health  for  the  Philippines,  wrote  as 
follows  in  the  Philippine  Journal  of  Science,  in 
February,  1914. 

Unusual  Character  of  Plague  at  Quarantine. — 
It  is  perhaps  worthy  of  note  that,  prior  to  the  appearance 
of  plague  in  Manila  a  number  of  cases  of  the  disease  were 
found  on  incoming  steamers.  For  instance,  on  April  6, 
1912,  a  death  was  reported  on  the  steamship  Zafiro,  which 
had  arrived  the  day  previous  from  Hongkong  and  had 
been  in  the  harbor  for  twenty-four  hours  at  the  time  of 
the  death.  At  the  medical  inspection  of  the  vessel,  which 
was  made  the  day  previous,  no  illness  was  detected.  An 
investigation  showed  that  the  victim  had  been  on  deck  on 
the  night  of  April  5,  1912,  in  apparently  good  health. 
The  next  morning,  at  6  o'clock,  he  was  found  dead  in  his 


ITS  CONTROL  AND  SUPPRESSION        59 

bunk.  The  necropsy  and  subsequent  biological  findings 
reported  by  Dr.  R.  P.  Strong  of  the  Bureau  of  Science 
showed  that  death  was  due  to  pneumonic  plague. 

On  April  7,  1912,  the  steamer  Loongsang  arrived  in 
Manila  from  Hongkong,  and  the  captain  reported  that  a 
death  had  occurred  the  day  previous  in  a  Chinese  member 
of  the  crew.  Upon  investigation  of  this  case,  the  captain 
stated  that  the  man  was  apparently  in  good  health,  but 
that  while  hauling  on  a  rope  he  fell  over  in  an  apparent 
faint  and  was  placed  in  a  chair  and  in  the  course  of  a  few 
hours  expired.  The  necropsy  and  animal  inoculations 
showed  that  he  had  died  of  plague  and  probably  of  the 
pneumonic  variety. 

Beginning  April  7,  1912,  the  temperature  of  all  mem- 
bers of  the  crew  and  of  the  passengers  that  arrived  in 
vessels  from  foreign  ports  was  taken  with  a  view  to  de- 
tecting any  possible  cases  of  plague. 

On  the  arrival  of  the  steamship  Taisang  from  Amoy 
at  the  Mariveles  Quarantine  Station  at  about  6.30  a.m. 
on  April  30,  1912,  the  entire  personnel  was  carefully  ex- 
amined and  found  free  from  sickness  of  a  suspicious  nature 
and  from  elevations  of  temperature.  Seventy-three  per- 
sons were  detained  to  serve  a  quarantine  detention  of 
seven  days.  On  the  evening  of  April  30,  a  Chinese  pas- 
senger, aged  fifty-one  years,  was  found  to  have  a  tem- 
perature of  39°  C.  with  a  pulse  of  100.  He  was  placed  in 
the  hospital,  but  protested  vehemently  that  he  was  not 
sick.  He  was  carefully  watched  from  the  first ;  there  was 
a  slight  cough ;  physical  examination  of  the  chest  revealed 
a  few  rales;  smears  made  of  the  sputum  and  stained  for 
plague  bacilli  were  negative.  On  the  fifth  day,  the  fever 
still  persisted,  but  the  patient  stated  that  he  did  not  feel 
ill  and  demanded  to  be  released  from  the  hospital.     On 


60  PLAGUE 

this  day,  the  expectoration  was  blood-stained,  but  no  sus- 
picious organisms  could  be  found  in  the  smears  nor  could 
any  physical  signs  of  pneumonia  be  detected.  Further- . 
more,  there  were  no  palpable  glands.  On  the  morning  of 
the  seventh  day,  the  temperature  and  pulse  dropped  and 
the  general  condition  was  distinctly  worse.  The  patient 
now  admitted  that  he  felt  ill.  Several  hours  later,  he 
flinched  when  pressure  was  made  in  the  right  axilla. 
Lymphatic  enlargement  was  now  made  out,  and  by  the 
evening  of  the  seventh  day  the  bubo  in  the  axilla  had  in- 
creased markedly  in  size,  the  swelling  approximating  3 
by  7  centimetres.  Glands  now  became  palpable  in  other 
portions  of  the  body,  particularly  in  the  cervical  region, 
and  a  few  hours  later  there  were  inguinal  and  femoral 
buboes.  The  patient  became  rapidly  worse,  and  died  at 
7  o'clock  on  the  morning  of  the  eighth  day  of  his  illness. 
At  the  necropsy,  the  glands  of  the  right  axilla  and  those 
of  the  right  side  of  the  neck  were  found  enlarged;  the 
other  lymphatic  glands  were  also  enlarged,  but  to  a  lesser 
degree.  There  was  consolidation  of  the  lower  lobe  of  the 
right  lung,  and  the  spleen  was  about  twice  its  normal  size. 
In  brief,  the  necropsy  findings  of  a  typical  case  of  sep- 
ticsemic  plague  were  present.  Smears  from  the  spleen  and 
the  right  axillary  gland  showed  immense  numbers  of 
bipolar-staining  organisms.  Cidtures  made  from  fresh 
pieces  of  tissues  and  later  inoculated  into  animals  gave 
positive  results  for  plague. 

Beginning  of  the  Manila  Epidemic. — Pro- 
ceeding with  the  Manila  epidemic  inaugurated  with 
the  two  cases  referred  to  as  recorded  in  June,  1912, 
we  find  that  the  total  number  of  cases  recorded 


ITS  CONTROL  AND  SUPPRESSION        61 

from  the  time  of  the  outbreak  in  1912  until  the  last 
case  in  1914  was  90.  (This  includes  none  of  the 
imported  cases  from  China  which  developed  en 
route  to  Manila  from  Chinese  ports.) 

Of  these  90  human  cases,  76  were  fatal  and 
autopsies  were  performed  in  all  instances.  Four- 
teen persons  recovered.  The  number  of  cases  of 
animal  plague  up  to  July,  1914,  was  53.  This 
refers  only  to  laboratory-proven  cases  of  rat  plague. 
As  a  matter  of  fact,  hundreds  of  dead  rats,  almost 
certainly  plague  rats,  were  found  in  the  course  of 
rat-proofing  operations. 

Although  the  period  covered  by  this  epidemic 
approximates  two  years,  it  must  not  be  supposed 
that  the  progress  and  extension  of  the  epidemic  was 
an  uninterrupted  or  unobstructed  one. 

On  the  contrary,  such  extension  as  occurred  was 
made  in  spite  of  the  most  active  suppressive  effort, 
and  it  is  beheved  that  this  effort  brought  about  a 
creditable  result,  as  indicated  by  the  accompanying 
record. 

When  one  considers  the  favorable  conditions 
for  the  natural  spread  of  plague,  both  in  Manila 
and  throughout  the  Philippine  Islands,  and  realizes 
the  interposed  difficulties  and  obstructions,  natural 


62  PLAGUE 

and  unnatural,  geographic,  human  and  domestic, 
which  confront  us  at  every  turn  of  the  path  to 
correction,  removal  and  reformation,  our  success 
in  checking  the  spread  of  plague  appears  as  a  real 
achievement,  especially  when  contrasted  with  the 
results  of  effort  during  the  same  period  in  a  British 
city  of  similar  size  but  a  few  days'  sail  from  Manila, 
where  the  cases  were  numbered  by  thousands  and 
where  the  infection  still  persists. 

First  Manila  Cases. — The  first  case  of  plague 
(June  12,  1912)  occurred  in  a  resident  of  Tondo, 
920  Calle  Antonio  Rivera,  and  in  the  light  of  sub- 
sequent developments  it  may  perhaps  be  grouped 
with  the  October  cases  traced  to  the  Manila  Railway 
Company's  freight  station  and  yard,  as  920  Calle 
Antonio  Rivera  is  but  a  stone's  throw  from  the 
Manila  Railway  property.  The  connection,  how- 
ever, is  not  clear,  and,  on  the  other  hand,  it  is  not 
wholly  inconceivable  that  the  rat  epidemic  and  hu- 
man plague  cases  at  the  railway  station  in  October 
may  have  been  secondary  to  this  July  case.  Such 
speculation  is  fruitless,  however,  so  far  as  establish- 
ing facts  is  concerned. 

The  second  case  of  human  plague  occurred  13 
days  later,  June  25,  in  a  resident  of  a  district  some- 


ITS  CONTROL  AND  SUPPRESSION        63 

what  removed  from  the  first  case,  but  in  the  same 
general  section  of  the  city. 

Then  came  a  lull  of  more  than  a  month,  until 
August  4,  during  which  time  no  case  of  plague 
occurred;  or  at  least  none  was  reported. 

August  brought  forth  five  cases  on  the  fourth, 
eighth,  fifteenth,  and  twenty-first  days  of  the  month, 
in  residents  of  the  Quiapo  and  Binondo  districts. 

These  cases  were  unrelated  to  the  preceding  ones 
so  far  as  could  be  ascertained. 

Another  lull  of  a  month,  until  September  24, 
now  occurred  without  a  reported  case  of  human 
plague.  During  this  time,  however,  the  first  cases 
of  rat  plague  were  discovered,  one  on  August  30 
and  two  on  September  6,  all  of  them  in  the  Quiapo 
district. 

From  this  time  (September  24)  on,  however, 
human  cases  occurred  at  intervals  of  a  few  days 
until  Christmas  Day,  1912,  the  longest  plague-free 
period  being  one  week;  the  number  of  cases  by 
calendar  months  being  distributed  as  follows :  Sep- 
tember, 3  cases;  October,  22  cases;  November,  12 
cases;  and  December,  6  cases. 

Geographic  Grouping. — Not  until  October  21 
was  there  any  apparent  geographic  grouping  of 


64  PLAGUE 

cases  indicating  a  well  localized  infected  centre. 
Upon  this  date  there  began  the  outbreak  of  plague 
among  the  employees  of  the  Manila  Railway  Com- 
pany, laborers  at  the  freight  station  and  yard  of 
the  company.  This  freight  station  and  yard  is  lo- 
cated between  Calle  Azcarraga,  Calle  Dagupan  and 
Calle  Antonio  Rivera.  The  outbreak  totalled  17 
human  cases,  all  fatal,  and  extended  into  Novem- 
ber. Indeed,  the  last  case  traced  to  this  focus  oc- 
curred on  December  7,  1912. 

During  the  present  epidemic  of  plague  in  Manila 
this  focus  was  the  only  one  to  which  a  larger  number 
of  cases  than  five  could  be  traced,  and  in  all  the 
other  instances  where  multiple  cases  were  traced  to 
an  infected  centre,  the  foci  were  all  single  buildings. 

The  locations  giving  rise  to  multiple  infections 
and  the  number  of  cases  of  plague  developing  at 
each  address,  with  months  of  incidence,  are  as  fol- 
lows: Calle  San  Fernando  (804-814),  November, 
1912,  4  cases;  Calle  Teodoro  Alonzo  (518) ,  Novem- 
ber and  December,  1912,  2  cases;  Calle  Cabildo 
(Intramuros),  November  and  December,  1912,  2 
cases;  Calle  Comercio  (1028),  February,  1913,  2 
cases;  Calle  Sande  (1364),  April,  1913,  5  cases; 
Calle  Juan  Luna  (1226),  May,  1913,  2  cases. 


ITS  CONTROL  AND  SUPPRESSION        65 

Returning  to  the  Manila  Railway  outbreak,  it 
is  necessary  to  state  that  a  well-defined  epidemic 
among  rats  preceded  this  outbreak,  resulting  in  the 
death  of  a  large  number  of  rodents  (undoubtedly 
from  rat  plague) .  This  epidemic  was  not  reported 
by  the  railroad  company  until  the  outbreak  of  hu- 
man plague  had  begun.  It  was  then  too  late  to 
identify  plague  in  the  dead  and  mummified  rats 
found  under  floors,  platforms  and  elsewhere,  but 
the  fact  that  large  numbers  of  rats  had  recently 
died  here  was  established  by  the  unanimous  testi- 
mony of  the  employees  at  the  freight  station  and 
the  finding  of  rat  cadavers. 

As  stated,  the  human  outbreak  here  occurred 
upon  October  21,  and  fifteen  cases  developed  within 
3  days. 

This  indicates  an  extensive  desertion  of  fleas 
from  plague  rat  cadavers  and  an  attack  upon  hu- 
man beings,  after  a  fasting  period,  on  the  part  of 
the  fleas,  of  several  days.  The  human  outbreak 
at  the  station  and  the  death  of  a  large  number  of 
rats  at  the  same  place,  just  previous,  correspond  to 
a  nicety  and  establish  to  a  moral  certainty  the  con- 
nection necessary  to  explain  the  epidemic. 

After  the  railway  epidemic  of  human  plague, 


66  PLAGUE 

cases  continued  to  occur  through  November  and 
December,  without  apparent  relation  to  each  other, 
except  in  the  following  instances,  which  have  already- 
been  mentioned: 

Four  cases  under  one  roof  on  Calle  San  Fer- 
nando (November  12,  13,  16  and  22)  ;  2  cases  in 
one  house  on  Calle  Teodoro  Alonzo  (November  26 
and  December  2) ;  and  2  cases  in  the  same  house 
on  Calle  Cabildo  (Intramuros),  November  23  and 
December  11. 

These  multiple  cases  will  be  referred  to  else- 
where. 

The  other  cases  during  October,  November  and 
December  were  apparently  sporadic  and  unrelated, 
either  to  the  other  human  cases  or  to  the  few  scat- 
tering cases  of  rat  plague  discovered  from  time  to 
time.  Without  doubt,  however,  all  were  actually 
related  to  preceding  cases  of  rat  plague,  i.e.j  to  un- 
discovered rat  cadavers,  dead  from  plague  and 
deserted  by  infected  fleas. 

In  the  following  plague  houses  (see  list  of  cases) 
dead  rats  were  actually  found,  although  the  ad- 
vanced degree  of  desiccation  and  mummification 
defeated  the  biologic  determination  of  the  cause  of 


ITS  CONTROL  AND  SUPPRESSION        67 

death:  518  Calle  Teodoro  Alonzo;  973  Calle  Azcar- 
raga;  282  Estero  de  Binondo. 

In  other  plague  houses  the  recent  finding  of 
dead  rats  was  alleged  by  the  occupants,  but  rather 
too  indefinitely  to  record  positively. 

A  study  of  the  maps  and  lists  showing  the  local- 
ities in  which  cases  of  rat  plague  had  been  found  up 
to  this  time  (December  26,  1912),  in  connection 
with  the  location  of  plague  houses,  was  much  less 
suggestive  than  a  similar  study  of  the  lists  and  maps 
covering  the  cases  of  1913. 

However,  the  existence  of  concurrent  rat  plague 
and  human  plague,  in  corresponding  sections  of 
Manila,  had  been  well  established  already  by  bac- 
teriologic  studies  of  captured  rats,  made  at  the 
Bureau  of  Science. 

Of  nearly  equal  weight  was  the  observation  con- 
cerning the  two  epidemics,  rat  and  human,  at  the 
Railway  Station,  which  I  have  already  described. 

The  year  1912  closed,  then,  with  a  recorded  total 
of  50  human  cases  and  7  verified  cases  of  rat  plague. 

January,  1913,  saw  but  a  single  case  of  human 
plague.  This  occurred  on  January  24,  just  a  month 
from  the  last  previous  case,  that  of  Christmas  Day. 


68  PLAGUE 

During  this  month  no  case  of  rat  plague  was 
reported. 

In  February,  3  human  cases  occurred  and  in 
March,  4  cases  were  recorded. 

Early  in  March,  1913,  cases  of  rat  plague  began 
to  occur  in  the  Tondo  district  in  a  section  lying  be- 
tween Manila  Bay  and  the  Estero  de  la  Reina  and 
extending  northward  from  Calle  Moriones.  This 
was  a  new  district  for  rat  plague  and  as  the  cases 
increased  in  number  we  were  able  to  foresee  and 
predict  the  appearance  of  human  plague  in  the  same 
district,  which  in  point  of  congestion  of  population, 
poverty  of  its  residents  and  in  the  matter  of  dilapi- 
dation of  its  light  material  houses  and  shacks,  is 
about  the  worst  locality  in  Manila. 

From  March  22  to  September  20,  1913,  all  the 
cases  of  human  plague,  11  in  number,  occurred  in 
the  midst  of  this  district.  During  the  same  period 
25  cases  of  rat  plague  were  reported  from  the  same 
section,  and  a  glance  at  a  map  of  this  part  of  Tondo 
instantly  shows  the  relationship  existing  here  be- 
tween rat  plague  and  human  plague. 

This  relationship  is  additionally  emphasized  by 
referring  to  the  memoranda  concerning  certain  over- 
crowded houses,  in  the  midst  of  the  rat  plague  dis- 


3    H 


£  ^ 


ITS  CONTROL  AND  SUPPRESSION        69 

trict,  where  multiple  human  cases  occurred.  (See 
memoranda  in  re  1226  Calle  Juan  Luna  and  1364 
Calle  Sande.) 

The  human  cases  in  April  were  5  in  number,  all 
originating  in  the  same  house,  and  the  May  cases 
numbered  4,  two  of  which  occurred  in  the  same 
house. 

It  may  be  explained,  in  passing,  that  two  cases 
of  human  plague,  discovered  in  Malolos,  25  miles 
from  Manila,  on  March  23  and  March  26,  respec- 
tively, were  definitely  traced  to  the  same  house  in 
Manila,  number  12  Calle  Aguila,  Tondo,  both  pa- 
tients having  lived  in  the  basement  of  this  house 
until  witliin  48  hours  of  the  development  of  the 
disease.  These  persons  were  unrelated  and  were 
two  of  a  large  number  of  people  who  lived  in  a  tene- 
ment at  this  address.  Both  patients  were  detected, 
while  still  alive,  in  Malolos,  where  they  were  Hving 
in  different  and  widely  separated  houses.  One  of 
the  patients  died  in  Malolos  but  the  other  one  was 
brought  to  Manila  by  train  and  died  at  San  Lazaro 
Hospital.  Fortunately  no  infection  was  transferred 
to  Malolos  by  these  two  persons.  In  this  connec- 
tion it  is  interesting  to  note  that  no  other  cases  have 
been  reported  from  outside  of  Manila,  except  the 


70  PLAGUE 

small  outbreak  in  Iloilo  in  the  southern  islands, 
where  the  antiplague  work  was  successfully  directed 
by  Dr.  Carroll  Fox.  Concerning  this  outbreak, 
Dr.  Heiser,  then  Director  of  Health  for  the  Philip- 
pines, writes  as  follows  (Philippine  Journal  of 
Science,  February,  1914) ; 

Plague  in  Iloilo. — In  Iloilo,  a  case  suspicious  of 
plague  was  reported  on  July  5,  1912,  and  this  diagnosis 
was  subsequently  confirmed  by  the  laboratory.  It  oc- 
curred in  the  person  of  a  Chinaman  who  was  reported  to 
have  come  from  Bais,  Oriental  Negros,  but  later  inves- 
tigation showed  that  he  had  been  a  resident  of  Iloilo  at 
least  since  February,  1912.  The  next  case  was  reported 
August  18,  and  the  last  case,  September  17,  1912.  There 
was  a  total  of  9  cases.  All  of  the  cases  were  confined  to 
two  houses.  During  July,  August,  September,  and  Oc- 
tober, 1146  rats  were  caught  in  the  vicinity  of  the  houses 
in  which  the  human  cases  had  occurred,  along  the  water 
front,  and  in  the  places  which  were  regarded  as  suspicious, 
but  in  not  a  single  instance  was  an  infected  rat  found. 

Directed  to  Take  Charge  of  Plague  Sup- 
pressive Measures. — Upon  my  arrival  in  Manila 
from  the  United  States,  on  October  23,  1912,  I 
received  orders  from  the  Director  of  Health  to  take 
charge  of  all  plague  suppressive  measures  in  Manila 
and  I  remained  in  charge  of  this  work  continuously 
until  July  11,  1914. 


ITS  CONTROL  AND  SUPPRESSION        71 

Plague  Fighting  Organization. — The  plague 
fighting  organization  was  composed  of  three  Amer- 
ican Sanitary  Inspectors  and  from  ten  to  fifteen 
native  Assistant  Sanitary  Inspectors  of  the  Bureau 
of  Health,  rat  catchers  and  laborers  of  the  Bureau 
and  laborers  of  the  City  of  Manila  supplied  by  the 
Department  of  Sanitation  and  Transportation.  The 
combined  force  varied  in  numerical  strength  from 
100  to  150  men  and  was  usually  divided  into  three 
parties,  distributed  in  various  parts  of  the  city  ac- 
cording to  the  local  indications  and  needs  from  time 
to  time. 

After  the  invasion  of  Tondo  by  rat  plague  we 
made  special  effort  to  rat-proof  the  light  material 
houses  of  that  section,  in  the  course  of  our  cleaning 
operations,  by  the  closure  of  the  open  ends  of  bam- 
boo timbers  with  cement  and  with  tin  cans,  in  the 
manner  shown  in  photographs  herewith.  In  addi- 
tion to  this,  special  attention  was  given  to  the  repair 
of  broken  cement  work,  and  hundreds  of  Bureau  of 
Health  orders,  verbal  and  written,  were  issued  to 
owners,  at  my  request,  in  the  rat  plague  districts. 

The  number  of  houses  in  which  bamboo  timbers 
were  closed  by  cement  or  tin  exceeded  a  thousand. 

In  addition  to  these  means,  the  very  important 


72  PLAGUE 

matter  of  depopulating  the  insanitary  basements 
of  the  light  material  houses  in  squares  where  plague 
has  occurred  was  given  attention,  with  the  result 
that  hundreds  of  families  were  moved  from  these 
insanitary  and  dangerous  ground-floor  rooms  to 
quarters  well  above  ground  and  measurably  removed 
from  the  rats,  which  roam  over  the  ground  from 
house  to  house,  foraging  for  food  under  kitchens 
and  in  gi'ound-floor  storerooms,  tiendas  and  eating 
places.  The  fish  packing  factories  aiFord  them 
abundant  food  and  a  number  of  cases  of  plague 
have  occurred  adjacent  to  these  fish-drying  estab- 
lishments. 

Rat-proofing  and  Rat  Destruction. — While 
it  is  frankly  admitted  that  rats  may  not  be  com- 
pletely exterminated  by  poisoning  and  trapping,  the 
statement,  so  frequently  repeated  of  late,  that  de- 
structive measures  really  increase  their  number,  is 
unwarranted  and  unsustained  by  facts,  at  least  in 
Manila.  It  seems  to  be  the  common  practice  for 
disbelievers  in  trapping  and  poisoning  to  array  the 
methods  of  rat-proofing  and  rat  destruction  as 
alternative  policies,  whereas  everyone  practically 
familiar  with  the  work  in  such  cities  as  Manila — or 
even  in  the  United  States — ^knows  that  there  is  often 


ITS  CONTROL  AND  SUPPRESSION        73 

no  choice  permitted.  Rat-proofing  is  highly  desir- 
able, permanent  in  its  results,  and  in  every  respect 
the  "  method  of  election."  On  the  other  hand,  it  is 
entirely  inapplicable  at  certain  times  and  in  certain 
localities  where  poverty,  lack  of  interest  of  property 
owners,  and  ofttimes  lack  of  interest  and  of  money 
on  the  part  of  municipalities,  absolutely  preclude  its 
immediate  application.  It  is  therefore  unfortunate 
that  the  statement,  that  rat  poisoning  and  trapping 
are  ineffective,  either  in  controlling  plague  or  in 
reducing  the  numbers  of  rats,  is  circulated.  It  may 
be  shown  easily,  by  the  daily  records,  that  within  a 
few  weeks  after  extensive  rat  poisoning  and  trap- 
ping (with  the  breaking  up  of  nests)  is  pursued  in 
a  given  locality,  the  rat  catch  drops  in  the  most 
decided  manner. 

Individual  premises  may  be  practically  cleared 
of  rats  by  continued  intelligent  rat  catching  and 
poisoning,  and  while  the  normal  rat  birth-rate  may 
keep  pace  with  the  normal  rat  death-rate  it  will  not 
keep  pace  with  the  normal  death-rate  plus  the  poi- 
soning and  trapping  death-rate  in  any  given  locality, 
provided  that  the  poisoning  and  trapping,  with  the 
destruction  of  nests,  be  intelligently  and  continu- 
ously carried  out. 

Rat-proofing  and  rat  destruction,  then,  should 


74  PLAGUE 

not  be  contrasted  as  alternative  procedures  or 
policies.  Both  are  valuable  and  each  has  a  proper 
place.  In  communities  non-infected  with  plague 
and  unexposed  to  infection  it  will  probably  be  found 
that  rat-proofing,  carried  out  in  connection  with  the 
repairs  of  old  buildings  and  the  erection  of  new 
ones,  will  meet  the  requirements.  On  the  other 
hand,  in  cities  exposed  to  plague  infection  or 
already  infected,  rat  destruction  is  bound  to  be 
necessary  for  years  to  come. 

In  emergency,  the  removal  of  people  from  in- 
timate relationship  with  rats  (so  far  as  is  possible), 
as  practised  recently  in  Tondo  district,  Manila, 
will  often  have  to  take  the  place  of  rat-proofing ;  and 
rat  destruction  and  expulsion  will  be  found,  in  the 
last  analysis,  to  be  the  methods  upon  which  success 
or  failure  in  fighting  plague  during  epidemic  time 
will  depend. 

In  this  connection  I  quote  correspondence  which 
passed  between  the  Director  of  Health  and  myself 
in  1913. 

Upon  March  22,  1913,  I  directed  the  following  letter 
to  the  Director  of  Health: 

Sir  :  I  have  the  honor  to  state  that  Estaban  Masibac, 
aged  twenty-two,  laborer,  who  died  at  140  Perla  of  bu- 
bonic plague,  slept  upon  the  ground  floor  of  this  house 
upon  a  bamboo  bed.    All  these  basement  dwellers  in  this  dis- 


ITS  CONTROL  AND  SUPPRESSION        75 

trict  now  infected  with  rat  plague  are  in  considerable 
danger. 

The  roving  rats  which  wander  over  these  ground  sur- 
faces from  house  to  house  come  into  pretty  close  contact 
with  these  basement  dwellers,  and  it  would  appear  that 
they  visit  the  upper  stories  of  the  houses  rather  infre- 
quently, unless  food  is  stored  there.  Upon  the  ground 
they  forage  upon  the  food  dropped  there  by  the  residents 
of  the  houses. 

I  would  like  to  have  authority  to  order  the  vacation 
of  these  basement  rooms  which  are  almost  invariably  unfit 
for  human  habitations. 

I  look  upon  this  measure  as  an  important  one  at  this 
threatening  time  and  believe  it  should  be  enforced  in  every 
square  or  block  where  plague  rats  have  recently  been 
found.  If  this  authority  is  granted  it  will  be  used 
judiciously. 

Very  respectfully, 

[Signed]  T.  W.  Jackson, 

Medical  Inspector  in  Charge  of  Plague  'Suppression. 

Upon  March  24  I  received  the  following  letter 
of  authorization: 

Sir:  Confirming  my  verbal  instructions  of  yesterday 
I  have  to  request  that,  in  accordance  with  the  recom- 
mendation contained  in  your  letter  of  March  22,  that  on 
account  of  the  danger  of  the  spread  of  plague  in  the  dis- 
trict in  which  plague  has  appeared  extensively,  the  base- 
ment dwellers  in  blocks,  or  squares,  in  which  plague  has 
been  found,  should  be  ordered  to  vacate. 
Very  respectfully, 

[Signed]  Victor  G.  Heiser, 

Director  of  Health. 


76  PLAGUE 

Upon  November  26,  1912,  five  dead  rats  were 
reported  from  the  U.  S.  Army  Comimissary  Ware- 
houses on  the  Pasig  River  near  the  Malecon.  They 
were  found  dead  by  workmen  there  and  were  thrown 
into  the  river  by  the  finders  and  thus,  unfortunately, 
examination  for  plague  was  prevented. 

Upon  November  27,  a  cat,  known  to  have  caught 
and  eaten  rats  recently  at  the  same  place,  was  re- 
ported to  be  sick.  I  took  the  cat  to  the  Bureau  of 
Science  where  she  was  observed  until  she  died,  three 
days  later. 

At  autopsy,  typical  bubonic  plague  (cervical) 
was  disclosed,  and  several  guinea-pigs  inoculated 
from  the  spleen  and  bubo  died  from  the  same  dis- 
ease. A  guinea-pig,  inoculated  from  a  swab  intro- 
duced into  the  cat's  rectum,  also  died  from  plague 
(see  report  of  Dr.  Schobl) . 

Four  kittens,  recently  born  of  this  plague  cat, 
were  observed  for  two  weeks  but  showed  no  sign  of 
the  disease. 

Subsequently  about  80  rats  were  caught  at  these 
warehouses  and  in  the  vicinity,  but  none  of  them 
showed  post-mortem  signs  of  plague.  The  Medical 
Department,  U.  S.  Army,  then  took  up  the  matter 
of  rat  catching  on  all  military  reservations  in  Manila 


ITS  CONTROL  AND  SUPPRESSION        77 

and  in  all  buildings  thereon,  but  no  more  oases  of 
animal  plague  were  discovered. 

Fleas  and  Their  Habits. — In  "  Observations 
Upon  the  Bionomics  of  Fleas  Bearing  Upon  the 
Epidemiology  of  Plague  in  Eastern  Java,"  by 
N.  H.  Swellengrebel,  Ph.D.,  published  by  the  gov- 
ernment at  Batavia,  Dutch  India,  in  1913,  some  in- 
teresting facts,  developed  by  study  and  experimen- 
tation, are  presented.  Some  of  these  facts  have  a 
bearing  on  the  plague  problem  in  the  Philippines, 
for  it  should  be  borne  in  mind  that  certain  climatic 
similarities  and  racial  similarities  pertain  commonly 
to  the  Javanese  and  Filipinos  and  their  respective 
countries. 

While  we  are  not  prepared  at  present  to  make 
general  application  of  the  Javanese  findings  to  the 
Philippine  Islands,  for  lack  of  parallel  or  confirma- 
tory studies  in  the  Philippines,  we  may  state  some 
of  the  conclusions  of  the  Java  workers  with  pro- 
priety, and  we  may  also  point  out  similarities  in  the 
construction  of  certain  Filipino  and  Javanese  habi- 
tations in  their  relation  to  rat  harboring. 

Swellengrebel,  in  Java,  noted  the  nimiber  of 
fleas  per  rat,  dealing  with  Xenopsylla  cheopis  (the 
commonest  rat  flea  in  Java)   almost  exclusively. 


78  PLAGUE 

This  flea,  it  will  be  remembered,  is  also  the  common 
rat  flea  of  India,  the  Philippines,  Australia,  Italy, 
Brazil  and  tropical  countries  generally,  being  vari- 
ously known  as  Loemopsylla  cheopis,  Puleoc  pal- 
lidus,  P,  hrasiliensis,  P.  philippinensis,  and  (in 
Italy)  P.  murimis. 

It  would  not  be  unreasonable,  therefore,  to  ex- 
pect to  find  at  least  some  of  his  observations  ap- 
plicable to  the  Philippine  Islands. 

SweEengrebel  failed  to  find  Ctenocephalus  cards 
(dog  flea),  C,  felis  (cat  flea)  and  Ceratophyllus 
fasciatas  (the  common  rat  flea  of  the  United  States 
and  Europe)  upon  Javanese  rats.  In  attempting 
to  determine  the  normal  flea  census  he  found  that 
field  rats,  and  field  rats  caught  indoors,  as  well, 
generally  carry  fewer  fleas  than  house  rats  and  that 
the  number  of  fleas  per  house  rat  varies  in  diff'erent 
districts  from  .02  per  rat  to  2.3  or  4  per  rat  and  that 
this  variation  is  not  invariably  constant  with  the 
presence  or  absence  of  rat  plague.  Concerning  the 
question  whether  or  not  a  high  flea  census  may  in- 
dicate rat  plague,  Swellengrebel  ofl'ers  the  reason- 
able opinion  that  there  is  little  doubt  that  plague  in 
rats  increases  the  number  of  fleas  per  rat  above 
normal  and  that,  consequently,  a  sudden  or  marked 


ITS  CONTROL  AND  SUPPRESSION        79 

increase  in  the  number  of  fleas  per  rat,  without  a 
known  normal  cause,  indicates  increased  rat  mor- 
tahty  and  probably  rat  plague. 

As  to  the  influence  of  temperature  and  humidity 
on  the  hatching  of  larvae,  he  concludes  from  experi- 
mentation that  the  duration  of  development  of  the 
egg  varies  under  various  hygrometric  conditions,  the 
general  rule  being,  "  the  lower  the  humidity  the 
longer  the  development  period." 

As  to  the  influences  of  temperature  and  humidity 
upon  the  transition  of  larva  to  imago  he  finds  that 
if  humidity  diminishes,  a  smaller  number  of  larvee 
reach  the  adult  stage;  and  also  that  a  saturated 
humidity  (in  artificial  cultures),  causing  condensa- 
tion of  water  in  the  substratum,  is  very  fatal  to 
larvEe.  He  offers  the  thought  that  this,  perhaps, 
explains  why  only  small  numbers  of  fleas  are  found 
on  field  rats  which  live  in  holes  in  rice  fields  which 
are  necessarily  damp,  especially  in  the  rainy  season. 

His  experiments  to  determine  the  duration  of 
life  of  fasting  fleas  were  made  with  laboratory-bred 
fleas  which  had  never  fed  on  blood  and  with  fleas 
which  had  already  sucked  blood. 

The  duration  of  life  was  variable,  but  of  those 
fleas  already  fed  with  blood  three-quarters   (^ 


80  PLAGUE 

perished  wdtliin  10  days  and  the  remainder  lived 
from  ten  to  twenty  days,  only  one-tenth,  however, 
sm-viving  for  13  days,  if  moist  conditions  were  main- 
tained. High  temperature  was  determined  to  be  an 
unfavorable  condition. 

If  from  these  findings  one  should  attempt  to 
predicate  or  predict  the  extension  of  plague  in 
house  rats — based  on  flea  prevalence — and  this  with 
relation  to  climatic  conditions,  we  should  be  led  to 
the  conclusion  that  the  rainy  season,  with  its  greater 
humidity,  would  be  quite  the  most  favorable  time 
of  year  for  rat  plague  extension  in  Manila  and, 
upon  the  contrary,  that  the  hot  dry  season  through 
its  unfavorable  influence  upon  flea  breeding  would 
be  the  least  favorable  season  for  rat  plague  in 
Manila. 

The  hot  months  of  1913  did  not  bear  out  this 
reasoning,  however,  for  during  these  months  rat 
plague  was  at  its  height. 

That  increased  prevalence  of  himian  plague  has 
not  gone  hand  in  hand  with  increased  prevalence  of 
rat  plague  in  Manila,  may  be  explained,  I  feel  sure, 
by  the  activity  of  our  efforts  to  destroy  rats  and  to 
remove  the  people  from  close  relationship  with  them. 

Another  factor  of  possible  explanation  of  the 


ITS  CONTROL  AND  SUPPRESSION        81 

greatest  prevalence  of  human  plague  in  Manila  dur- 
ing the  late  rainy  season  of  1912  (October),  is  the 
fact  that  rats  are  certainly  driven  above  ground 
into  houses  and  therefore  into  closer  relationship 
with  man  by  heavy  rainfall  and  the  consequent 
flooding  of  their  subterranean  homes. 

It  appears,  therefore,  that  the  seasonal  explana- 
tion of  greater  plague  prevalence,  rat  or  human,  is 
susceptible  of  several  interpretations  and  I  feel  sure 
that  in  countries  like  the  Philippines  seasonal  varia- 
tions in  heat  do  not  suffice  to  rid  the  rats  of  fleas  dur- 
ing any  months  of  the  year.  If,  then,  conditions  of 
rainfall  serve  to  drive  the  rats  above  ground  and 
indoors  during  certain  months,  it  would  be  reason- 
able to  expect  more  human  plague  from  closer  re- 
lationship of  rat  and  man, — provided  that  no  special 
measures  were  carried  out. 

Such,  however,  is  not  invariably  the  rule,  if  sta- 
tistical studies  are  to  be  taken  as  evidence,  and  so 
we  are  reminded  that  generalizations  for  countries 
of  different  chmates  and  seasons  are  not  wholly 
reliable. 

Rat  breeding,  as  well  as  flea  breeding,  is  in- 
fluenced by  climate,  but  as  the  reproductive  activity 
of  the  rat  is  most  retarded  by  cold  weather — an 

6 


82  PLAGUE 

unknown  condition  in  the  Philippines — and  as  the 
climate  of  Manila  is  fairly  equable  so  far  as  heat 
and  cold  are  concerned,  the  only  factor  which  needs 
to  be  considered  is  that  of  rainfall.  As  already  men- 
tioned, rainfall  doubtless  serves  to  drive  rats  above 
ground  and  so,  to  a  certain  extent,  away  from  their 
nests  in  burrows  and  underground. 

Their  well-known  adaptabihty  to  changing  con- 
ditions, however,  permits  them  to  house  themselves 
comfortably  above  ground  when  driven  out  of  these 
burrows  and  holes. 

Javan  Observations. — The  following  conclu- 
sions were  reached  by  Dr.  J.  J.  van  Loghem  in  a 
report  upon  "  Some  Epidemiological  Facts  Con- 
cerning the  Plague  in  Java  "  (published  by  Civil 
Medical  Service  in  Netherlands  India-Batavia, 
1912) : 

1.  In  plague-infected  villages,  as  distinguished  from 
plague-free  villages,  there  exists  a  considerable  mortality 
among  house  rats. 

2.  Rats  in  plague  houses  and  plague  quarters  have 
repeatedly  died  from  plague.  Fresh  plague  rats  appear 
more  often  in  the  houses  adjoining  plague  houses  than  in 
the  houses  themselves. 

3.  The  house  rat  exists  even  in  the  immediate  vicinity 
of  man. 

4j.  The  ordinary  parasite  of  the  house  rat  is  Xenop- 


ITS  CONTROL  AND  SUPPRESSION        83 

sylla  cheopis,  which  experimentally  is  known  to  choose 
man  as  a  host  when  starving. 

5.  Fresh  plague  rats  have  repeatedly  been  found  to 
harbor  a  great  number  of  fleas. 

6.  Virulent  plague  bacilli  have  been  demonstrated  in 
the  stomachs  of  such  fleas. 

Concerning  the  prevention  of  plague  by  improv- 
ing the  native  dwellings,  the  same  observer  says: 
"  Obviously  an  increase  in  the  distance  between  man 
and  rat  becomes  an  important  factor  as  a  means  of 
preventing  the  disease." 

Conditions  of  Manila  Habitations  Favor- 
able TO  Rats  and  Plague. — As  shown  by  our  own 
experiences  in  Manila,  this  end,  the  separation  of 
rats  and  men,  is  not  obtainable  by  destruction  of 
rats  by  poison,  traps  and  rat  catchers.  Rats  dying 
of  plague  in  their  nests  furnish  the  greatest  danger 
to  man.  The  plague  problem,  therefore,  where  rats 
are  already  infected,  from  the  stand-point  of  direct 
prophylaxis,  is  the  problem  of  dwellings.  It  was 
from  this  stand-point  that  we  attacked  the  problem 
in  the  Tondo  (Manila)  campaign  in  1913. 

Manila  Verification  of  Javan  Observa- 
tions.— Having  in  mind  the  experiences  of  the 
plague  investigators  in  Java  during  the  recent  epi- 
demics there   (1911-1912),  we  sought,  from  the 


84  PLAGUE 

time  the  Manila  outbreak  occurred,  to  verify  some 
of  the  findings  of  the  Java  investigators,  at  least 
with  special  reference  to  the  nesting  of  rats  in  close 
proximity  to  human  beings  and  the  consequent  ex- 
posure of  these  persons  to  the  infected  fleas  which 
desert  the  rats  dying  from  plague  in  these  nests. 

Not  until  rat  plague  invaded  the  special  district 
of  Tondo,  in  Manila,  in  March,  1913,  did  the  oppor- 
tunity present  itself.  Theretofore  the  Manila  cases 
had  generally  appeared  in  houses  of  the  so-called 
"  hard  material  districts,"  where  house  construction 
is  entirely  unlike  that  with  which  the  Java  workers 
dealt.  With  the  invasion  of  Tondo,  however,  the 
Java  and  Manila  conditions  became  similar.  I 
quote  the  descriptions  of  Javanese  house  construc- 
tion from  the  report  of  Dr.  J.  J.  Van  Loghem, 
"  Some  epidemiological  facts  concerning  the  plague 
in  Java,"  Batavia,  1912. 

The  Javan  Village  House. — In  substance,  he 
says  that  the  Java  village  house,  as  a  general  type, 
is  a  one-storied  structure  with  its  roof  sloping  to 
the  front  and  back,  i.e.,  with  its  ridge  parallel  with 
the  front  and  back  aspects  of  the  building.  It  is 
not  elevated  above  the  ground  by  supports  or  pali- 
sades and  has  no  separate  floor,  the  earth  serving  as 
the  floor. 


ITS  CONTROL  AND  SUPPRESSION        85 

The  outer  frame  is  of  strong  bamboo  poles  and 
the  inner  frame  is  also  constructed  of  bamboo. 
These  bamboo  timbers  are  perforated  at  various 
points  to  permit  of  framing  with  other  pieces  of 
bamboo  and  for  the  entrance  of  pegs,  etc. 

The  roofs  of  these  houses  are  often  made  of  tiles, 
but  at  times  the  familiar  thatched  roof  is  seen.  In 
both  cases  the  supports  or  rafters  are  bamboo  poles. 
The  principal  piece  of  furniture  is  the  "  bale  bale," 
or  bedstead,  usually  made  of  bamboo,  except  in  the 
houses  of  the  well-to-do.  Small  storerooms  are 
often  located  in  the  houses,  and  stables  are  some- 
times built  against  them.  In  many  cases  the  family 
provisions  are  kept  in  the  house  and  the  cattle  are 
housed  here  as  well. 

Manila  Light  Material  Houses. — If,  now, 
we  turn  our  attention  to  the  average  Tondo 
(Manila)  light  material  house  it  will  be  apparent 
that  the  description  given  for  the  Java  village  house 
fairly  describes  the  Tondo  house,  except  that  the 
Philippine  house  is  commonly  elevated  2  metres 
or  more  above  the  ground  upon  bamboo  supports 
(see  photographs).  The  basement  is  usually  en- 
closed in  a  manner  similar  to  the  principal  room  of 
the  Java  house  and  the  basement  room  may  fairly 


86  PLAGUE 

be  compared,  structurally  and  in  the  matter  of  its 
floor,  with  the  one-story  Java  house.  In  the  Manila 
house,  however,  the  floor  of  the  upper  room  takes 
the  place  of  the  roof  of  the  Java  house  and  like  it 
is  supported  by  bamboo  timbers. 

Here,  then,  in  our  enclosed  basement  story,  we 
have  a  practical  replica  of  the  one-storied  Java 
house. 

Here,  also,  the  principal  piece  of  furniture  is 
often  a  bamboo  bed,  practically  identical  with  the 
Java  "  bale  bale,"  if  we  may  judge  from  photo- 
graphs. 

In  the  Java  houses  the  favorite  nesting  places 
for  rats  were  found  to  be  the  interiors  of  horizontal 
bamboo  pieces  of  the  roof,  house  frame  and  bed- 
stead. 

The  rat  usually  gains  entrance  by  gnawing 
through  the  natural  partitions  between  the  bamboo 
sections  near  the  outer  end  of  the  pole.  Our  Manila 
photographs  show  both  the  natural  open  ends  of 
such  timbers  and  the  rat-gnawed  perforations  in  the 
partitions. 

In  Java,  rats  also  nest  in  the  thatched  roofs,  as 
they  occasionally  do  in  the  Philippines. 

Nest  Materials. — The  materials  utilized  for 


■'l   !     !     1    i  I    .    ,     ,  t    .'1    *        •        Hi.  I        .    ,  ,   ,  i  ,  .    i  ,    ,   i    i    ( 


TT 


rrrrrri"'     fpnrp--,  rn-i--'n 


^w]]^ 


|U^  I     !    !  !    t  !  li 


i-i  i     !      '  I  i  1  llH 


xLunijiij!  nm.iixi"!";]!""'  mnm 


BAMBOO  HOUSE  SUPPORTS  NOT  SEALED  WITH  CEMENT.    NOTE  HOLES  GNAWED  IN  BAMBOO 
ENDS.      RATS  FREQUENTLY  MAKE  NESTS  IN  THESE  HOLLOW  BAMBOO  RAFTERS. 


ITS  CONTROL  AND  SUPPRESSION        87 

nests  by  rats  in  Manila  and  Java  seem  to  be  iden- 
tical also.  Straw,  dry  leaves  and  pieces  of  cotton 
are  mentioned  in  the  Java  reports.  The  same  ma- 
terials and  additional  ones  will  be  found  mentioned 
in  our  reports  upon  nests. 

The  presence  of  food  was  also  noted  in  the 
bamboo  nests  in  Java  and  we  often  find  articles  of 
food  in  our  Manila  nests. 

Dr.  Kom,  P.  H.  Service,  and  the  writer 
( T.  W.  J. )  investigated  a  good  many  of  these  bam- 
boo house-timbers  and  we  not  only  found  such  evi- 
dences of  rats  as  food,  rat  faeces  and  nest  materials, 
but  in  one  case  a  rat  was  actually  driven  out  of  a 
bamboo  nest  by  introducing  a  long  thin  strip  of 
wood.  The  evidence  of  similar  conditions  then  is 
complete. 

We  also  duplicated  the  experiences  of  the  Java 
workers  in  finding  dead  rats  inside  of  the  bamboo 
house  timbers  in  close  proximity  to  patients  sick 
(or  dead)  with  plague  (see  memoranda  in  the  case 
of  Esteban  Masabik,  of  140  Calle  Perla,  March  22, 
1913). 

Very  extensive  rat  destruction  and  cleaning 
operations,  covering  a  large  portion  of  the  city  of 
Manila  and  including  all  sections  where  cases  of 


88  PLAGUE 

rat  plague  or  human  plague  developed,  were  under- 
taken and  this  work  was  carried  on  without  inter- 
ruption for  about  two  (2)  years.  City  laborers  to 
the  number  of  60  to  150  were  used  and  the  work  was 
supervised  by  Sanitary  Inspectors  Brantigan  and 
Searcy,  of  the  Bm-eau  of  Health.  During  a  part 
of  the  time  a  flying  column  of  50  men,  under  Sani- 
tary Inspector  Hunniecutt,  was  detached  from  the 
main  party  and  employed  at  placing  rat  poison. 

The  total  amount  of  accumulated  dirt  removed 
from  houses  and  yards  approximated  5250  tons  (for 
17  months  ending  November  1,  1913). 

Without  doubt  this  general  cleaning  campaign 
and  the  removal  of  this  enormous  accumulation  of 
dirt  and  rubbish  was  of  great  value  as  an  antiplague 
measure. 

The  rat  catch  will  always  be  found  to  depend 
upon  several  factors,  viz.:  the  number  of  persons 
employed;  the  number  of  traps  and  portions  of 
poison  placed ;  the  location  of  the  operations  and  the 
length  of  time  a  given  locality  is  trapped,  poisoned 
and  cleaned.  The  variety  of  baits  and  poisons  will 
also  affect  the  results. 

In  addition  to  these  factors  certain  others  are 
found  to  operate  in  reducing  the  rat  catch,  as,  for 


ITS  CONTROL  AND  SUPPRESSION        89 

example,  weather  conditions  and  the  occurrence  of 
Sundays,  hoKdays  and  the  days  just  preceding  and 
following  holidays. 

Upon  rainy  days  and  the  days  just  mentioned 
the  rat  catch  almost  invariably  falls  oiF. 

From  statistics  collected  by  me  in  connection 
with  this  work,  Dr.  V.  G.  Heiser,  then  Director  of 
Health  for  the  Philippine  Islands,  published  the 
following  memorandum  in  1914.  As  it  is  a  correct 
transcript  of  my  records  I  introduce  it  here  in  its 
entirety. 

Comparative  Statistics  in  Rat-catching  Methods.^ 
— With  a  view  to  ascertaining  which  type  of  rat  trap  was 
most  effective  and  also  the  average  number  of  rats  that 
are  caught  by  a  given  number  of  poisoned  baits  that  are 
set  out,  statistics  were  kept  during  the  antirat  campaign 
in  Manila.  The  ratio  maintained  in  catching  rats  with 
two  types  of  traps  is  indicated  in  the  following  table,  a 
perusal  of  which  will  show  that  for  the  three  months  ended 
June  30,  1913,  there  were  120,565  spring  or  snap  traps 
set  and  that  for  every  100  of  this  type  of  trap  set  there 
were  caught  6.9  rats.  During  the  same  period  there  were 
4*7,075  wire  cage  traps  set;  the  total  number  of  rats 
caught  was  339 ;  which  gives  0.72  rat  caught  for  each 
hundred  traps  set.  For  the  quarter  ended  September  30, 
130,627  spring  or  snap  traps  were  set  and  9,753  rats  were 

1  Reprint  from  the  Public  Health  Reports,  Vol.  29,  No.  6, 
February  6,  1914. 


90 


PLAGUE 


caught,  which  gives  7.47  for  each  100  traps  set.  During 
this  period  40,621  wire  cage  traps  were  set  and  395  rats 
were  caught,  which  gives  0.97  rat  caught  for  each  100 
wire  cage  traps  set. 


Quarter  ended  June  30 

Quarter  ended  Sept.  30 

Kind  of  trap  or  poison 

Number 
set 

Number 
of  rats 
caught 
or  poi- 
soned 

Per 

cent. 

Number 
set 

Number 
of  rats 
caught 
or  poi- 
soned 

Per 
cent. 

Spring  or  snap  traps. . 

Wire  cage  traps 

Poison  bacon,  rice,  or 
coconuts 

120,565 
47,075 

166,237 

8,377 
339 

1,216 

6.9 
.72 

.731 

130,627 
40,621 

177,309 

7,753 
395 

216 

7.47 

.97 
.12 

Quarter  ended — 

June  30 

Sept.  30 

Number  of  rats: 

Caught  by  dogs 

160 

2,889 

316 

5 

Killed  with  clubs  and  other  wfif.nnns 

3,818 

Found  dead  from  oth^T  rnnsf 

JS 

297 

No  accurate  record  was  kept  of  the  number  of  each 
kind  of  rat  bait  set.  Only  the  total  of  all  was  recorded. 
Bacon  or  coconut  with  strychnine  and  rice  with  arsenic 
were  used.  For  instance,  for  the  quarter  ended  June  30, 
1913,  there  were  166,237  poison  baits  set  in  new  territory 
and  the  rats  found  poisoned  average  for  each  100  baits 
0.72.  During  the  next  quarter  there  were  177,309  baits 
set  in  territory  that  had  been  worked  over,  and  only  216 
rats,  or  0.12  rat  per  100  baits,  were  killed.  From  the 
foregoing  it  appears  that  the  rat  poison  ranks  lowest  in 
efficiency  but  perhaps  highest  in  economy.    In  view  of  the 


ITS  CONTROL  AND  SUPPRESSION        91 

fact  that  the  original  cost  of  the  cage  trap  is  many  times 
more  than  that  of  the  spring  trap,  and  the  cost  of  main- 
tenance is  very  high,  it  will  be  apparent  that  the  spring 
trap  is  by  far  the  more  economical  as  well  as  more 
effective  of  the  two. 

Generally  speaking,  however,  the  number  of  rat 
catchers  engaged  and  the  location  of  their  operations 
has  the  largest  influence  upon  the  total  catch  of  rats. 
For  the  fiscal  year  July  1,  1912,  to  June  30,  1913, 
inclusive,  the  total  catch  was  55,101  rats  (Manila 
only) ;  to  December  1,  1913,  79,676. 

The  most  natural  explanation  of  the  general 
correspondence  between  the  highest  rat  catch  and 
the  highest  incidence  of  human  plague  would  be 
upon  grounds  of  greater  activity  in  rat  catching 
effort  at  times  of  greatest  plague  prevalence,  but 
from  the  inauguration  of  general  systematic  rat 
catching  there  was  no  cessation  of  effort,  even  dur- 
ing the  abatement  of  plague,  and  in  consequence 
this  explanation  does  not  apply  strictly. 

It  is  true,  however,  that  whenever  plague  oc- 
curred in  districts  theretofore  free  from  the  disease, 
rat  catching  was  pushed  vigorously  in  the  surround- 
ing localities. 

Making  due  allowance  for  all  the  factors  men- 
tioned I  am  impressed  with  the  probability,  amount- 


92  PLAGUE 

ing  almost  to  certainty,  that  the  catch  of  more  than 
79,676  rats  definitely  aiFected  and  checked  the 
spread  of  plague  in  Manila  in  1913;  and  I  am  of 
the  opinion  that  systematic  and  wholesale  rat 
catching,  carried  out  in  the  most  economical  man- 
ner possible,  should  be  persisted  in  indefinitely,  at 
least  imtil  plague  disappears,  wherever  the  disease 
occurs. 

Efforts  to  prevent  the  spread  of  plague  to  the 
provinces  of  Luzon,  by  way  of  the  railways,  were 
successful  and  the  present  measures  employed, 
freight  inspection,  the  fumigation  of  packages  sus- 
pected or  likely  to  contain  rats,  and  the  similar  treat- 
ment of  freight  cars  showing  signs  of  rats,  should 
be  continued.  In  a  few  cases  these  measures  have 
driven  rats  out  of  both  packages  and  cars  and  the 
animals  have  been  killed  by  the  sanitarians  on  duty 
at  the  station. 

The  matter  of  water  transportation  was  entirely 
within  the  control  of  the  authorities  in  charge  of 
inter-island  quarantine  aif  airs. 

Rat  catching  in  ^lanila  was  systematically  per- 
formed and  all  rats  captured  were  turned  over  to 
the  Bureau  of  Science  for  examination  for  plague. 

When  plague  foci  were  discovered  the  locahties 


ITS  CONTROL  AND  SUPPRESSION        93 

were  trapped  and  poisoned  both  circuniferentially 
and  centrally,  with  a  view  to  preventing  the  dif- 
fusion of  infected  rats  throughout  the  city. 

Rat-peoofing. — The  theoretic  desirability  and 
superiority  of  "  out  building  "  the  rat,  over  all  other 
methods  of  rat  suppression,  is  admitted.  The  ap- 
parent impracticability  of  actually  rat-proofing 
Manila  at  the  present  time  and  our  inabihty  to 
starve  the  animals  out,  justify  the  other  and  less 
permanent  measm^e,  viz. :  rat  catching.  However, 
I  heartily  favor  and  ui'ge  the  most  complete  and 
thorough-going  rat-proofing  of  buildings  actually 
infected  with  human  or  animal  plague,  in  all  cases. 
The  building  ordinances  of  Manila  already  provide 
for  rat-proof  construction  in  all  new  buildings 
erected. 

With  a  view  to  cutting  off  the  food  supply  of 
the  rat,  more  than  1100  orders  upon  householders, 
to  provide  covered  garbage  cans,  were  served  in  the 
district  of  Tondo  alone. 

The  open  ends  of  bamboo  timbers  in  more  than 
2300  houses  were  closed,  either  by  cement  or  tin 
cans,  during  1913. 

Theatre  Disinfection. — All  the  cinemato- 
graphs and  theatres  in  the  city  were  disinfected  upon 


94  PLAGUE 

repeated  occasions  by  spraying  with  petroleum  and 
cresols,  with  a  view  to  destroying  fleas  and  prevent- 
ing plague  infection. 

Attempts  at  deception  and  concealment  of 
plague  patients,  upon  the  part  of  members  of  their 
f amihes,  were  numerous,  but  with  the  close  scrutiny 
of  death  certificates  and  dead  bodies  exercised  at  all 
health  stations  it  is  believed  that  all  cases  were 
recognized. 

One  case  of  extremely  careless  diagnosis  oc- 
curred. A  death  certificate  was  furnished  by  a  local 
native  doctor  who  certified  the  cause  of  death  to  be 
"  uterine  hemorrhage."  Suspicion  arising,  an 
autopsy  was  ordered  and  a  pronounced  case  of 
bubonic  plague  was  disclosed  postmortem.  No  evi- 
dence of  uterine  hemorrhage,  except  slight  men- 
strual signs,  was  found. 

The  destruction  of  infected  fleas  in  plague 
houses  is  of  course  the  primary  object  of  the  disin- 
fection by  spraying,  which  is  thoroughly  carried  out 
in  every  house  where  a  case  of  human  plague  or  rat 
plague  appears.  The  method  is  a  simple  one  and 
consists  in  spraying  a  mixtm'e  of  cresols  ( 2  per  cent. ) 
and  kerosene  (98  per  cent.)  over  all  sm'faces  of  the 
house,  floors,  walls,  underlying  ground,  fm^niture 


ITS  CONTROL  AND  SUPPRESSION        95 

and  the  spaces  above  ceilings,  etc.,  using  the  mixture 
liberally  and  securing  a  general  surface  distribu- 
tion. There  is  no  doubt  of  the  toxicity  of  this  mixt- 
ui'e  to  all  fleas  and  bed-bugs  which  it  reaches,  and 
it  is  undoubtedly  an  effective  measure  in  rendering 
an  infected  house  safe.  All  of  the  instances  of 
multiple  house  infections,  where  the  cases  recurred 
after  disinfection,  in  Manila,  have  been  in  houses 
where,  for  one  reason  or  another,  the  recommended 
structural  rat-proofing  has  been  postponed  or  where 
it  has  not  been  done.  Thus,  on  Calle  San  Fernando 
the  sequence  of  the  four  cases  (their  progress  by 
days  and  in  consecutive  houses)  is  explained  by  the 
travel  of  rats  through  efiicient  rat  runs  present  in 
the  walls  and  ceilings,  rather  than  by  the  passage  of 
fleas  through  partition  walls,  from  uncommunicat- 
ing  house  to  house. 

So  also  at  Calle  Cabildo,  where  the  superstruc- 
ture of  the  house  was  a  veritable  sieve,  there  was  a 
series  of  communicating  double  walls. 

At  the  house  on  Calle  T.  Alonso  a  similar  con- 
dition existed,  but  here  the  two  cases  which  occurred 
may  have  been  synchronously  infected,  or  nearly  so, 
previous  to  disinfection  of  the  premises. 

At  Calle  Comercio,  where  six  days  elapsed  be- 


96  PLAGUE 

tween  two  cases,  the  rooms  and  building  were  piled 
full  of  merchandise,  defeating  immediate  disinfec- 
tion, that  is,  efficient  disinfection,  until  all  the  mer- 
chandise was  moved  and  the  rooms  were  emptied. 

At  1364  Calle  Sande,  Tondo,  where  5  cases 
originated,  the  infections  were  undoubtedly  almost 
synchronous  and  no  infection  occurred  after  disin- 
fection of  the  house,  while  at  1226  Calle  Juan  Luna, 
Tondo,  the  two  cases  were  plainly  infected  at  about 
the  same  time  and  this  previous  to  disinfecting  the 
premises. 

Guinea-pigs  as  Indicators  of  Infected 
Houses. — The  following  experiment  shows  strik- 
ingly the  necessity  for  disinfecting  houses  where 
hmnan  or  animal  plague  cases  have  occurred. 

Upon  December  17,  1912,  Dr.  O.  Schobl,  of  the 
Bureau  of  Science,  and  myself,  placed  two  healthy 
guinea-pigs,  free  from  fleas,  in  a  wire  trap  cage  in 
the  house  at  No.  4  Calle  Barraca,  a  few  hours  be- 
fore the  house  was  disinfected,  a  patient  with  plague 
from  this  house  having  died  within  the  preceding 
twelve  hours.  The  cage  containing  the  guinea-pigs 
was  placed  exactly  where  the  patient  had  slept  upon 
the  floor,  as  indicated  by  the  other  tenants  of  the 
house.    Disinfection  was  delayed  for  a  few  hours 


ITS  CONTROL  AND  SUPPRESSION        97 

and  the  guinea-pigs  were  left  in  the  house  for  one 
day.  Upon  December  21  one  of  the  guinea-pigs 
died  from  typical  bubonic  plague — anatomically  and 
bacteriologically  positive — other  inoculated  experi- 
mental animals  also  developing  the  disease. 

Other  guinea-pigs  placed  in  plague  houses  on 
Calle  Cabildo  and  Calle  San  Fernando,  after  dis- 
infection of  the  premises,  failed  to  acquire  plague. 

Natural  Enemies  of  the  Flea. — It  was  ob- 
served during  the  studies  in  Java  that  certain 
natural  enemies  of  fleas  exist  and  operate  against 
their  laboratory  cultivation  and  their  natural  re- 
production. 

Ants  of  several  varieties,  large  and  small  red 
ants  and  small  black  ones,  were  found  to  be  very 
antagonistic  to  fleas,  both  in  the  larval  and  adult 
states,  destroying  them  actively. 

Fleas  in  the  laboratory  were  found  to  be  affected 
with  mites,  with  a  resultant  high  mortality  among 
the  insects.  The  same  parasites  were  not  found 
upon  wild  fleas.  On  account  of  the  prevalence  of 
mites  upon  the  laboratory  fleas  certain  experiments 
concerning  the  transmission  of  plague  were  vitiated. 

The  activity  of  ants  in  attacking  and  disposing 

of  rat  cadavers  found  in  our  antiplague  work  in 
7 


98  PLAGUE 

IManila  was  frequently  brought  to  my  attention. 
We  invariably  included  an  attack  upon  ants  in 
treatment  of  houses  known  to  harbor,  or  suspected 
of  harboring,  plague  rats.  The  combination  of 
kerosene  and  cresols,  elsewhere  referred  to,  was 
found  to  be  perfectly  satisfactory  in  the  destruction 
of  ants;  assuming,  of  course,  that  the  necessary 
procedure  of  exposing  the  ants,  by  the  moving  of 
merchandise,  boards  or  other  protecting  materials, 
was  performed,  so  that  contact,  by  spraying  the  in- 
secticide mixture,  was  secm-ed. 

Activity  of  Fleas. — It  was  also  observed  dur- 
ing the  Java  studies  that  the  rat  flea,  while  rather 
lazy,  may  and  does  cover  distances  of  five  metres 
and  that  he  sometimes  covers  eighteen  centimetres 
at  a  single  leap. 

In  addition  to  this,  of  com'se,  there  must  be  con- 
sidered the  possibility  of  his  falling  considerable 
distances. 

ZooLOGic  Classification  of  Rats. — The  mat- 
ter of  accurately,  systematically  and  scientifically 
cataloguing  and  classifying  rats  is  one  of  great  diffi- 
culty and  is  not  to  be  midertaken  by  anyone  but  a 
trained  naturalist.  However,  some  of  the  notes  we 
have  at  our  disposal,  gathered  from  many  som-ces. 


ITS  CONTROL  AND  SUPPRESSION        99 

may  be  set  before  the  reader.  It  is  extremely  diffi- 
cult to  find  exact  correspondence  of  statement  in 
the  various  classifications  offered  by  writers  upon 
plague  and  rats. 

Dr.  Lantz  gives  the  following  brief  classification 
in  his  section  of  the  publication,  "  The  Rat  and  Its 
Relation  to  Public  Health." 

Order:   Rodentia. 

Family :   Muridce. 

Genus :   Mus. 

Species  are  many,  but  only  three  or  four  are  cosmo- 
politan. 

Cosmopolitan  species :  Mus  rattus — black,  brown,  and 
roof  {Alexandrine)  rat;  Mus  decumanus — gray,  barn, 
wharf,  sewer,  and  Norway  rat. 

Mus  rattus  has  many  varieties  known  through- 
out the  world  and  these  are  named  according  to  color 
and  habitat. 

In  addition  to  the  names  given  in  Lantz's  classi- 
fication, we  constantly  see  reference  to  the  black 
house  rat,  the  brownish-gray  rat  (Mus  Alexan- 
drinus),  the  ordinary  ship  rat,  the  field  rat,  etc.; 
terms  descriptive  of  habitat  and  appearance  being 
very  loosely  applied.  Little  account  is  taken,  by 
many,  of  the  well-known  variations  in  the  coloration 
of  rats  due  to  climate  and  season  and  of  the  well- 


100  PLAGUE 

recognized  aptitude  of  the  rat  for  living  in-door 
or  out-door  according  to  circumstances  of  food  sup- 
ply, weather,  etc.  The  "  sawah "  rat  of  Dutch 
India,  implicated  in  the  prevalence  of  plague  there, 
was  formerly  considered  a  variety  of  Mus  decu- 
manuSj  but  is  now  described  as  a  field  variety  of 
Mus  rattus.  So  too,  varieties  of  Mus  decumanus 
are  frequently  named  according  to  alleged  geo- 
graphic origin,  habitat,  color  and  habits,  viz. :  sewer 
rat,  brown  rat,  Norway  rat  and  migratory  rat. 

The  inevitable  confusion  bound  to  arise  from 
such  loose  classification  is  obvious. 

Another  genus,  Gunomys  (Nesokia) ,  implicated 
in  plague,  is  represented  in  India  by  two  species 
and  by  at  least  one  (an  undetermined  one)  in  Java, 
some  confusion  existing  in  the  matter  as  yet.  Mem- 
bers of  this  genus  are  described  as  large,  rough- 
coated  rats  which  live  both  as  house  rats  and  field 
rats.  In  India  the  Plague  Commission  reported 
specimens  of  this  genus  as  particularly  susceptible 
to  plague. 

In  the  Philippine  Islands  no  specimens  of 
Gunomys  have  been  observed,  but  31,  rattus  and 
31.  decumanus  are  both  present  and  numerous  and 
both  are  subject  to  plague,  as  shown  by  the  presence 
of  the  disease  in  specimens  examined. 


ITS  CONTROL  AND  SUPPRESSION      101 

In  view  of  the  unreliability  of  the  points  of  dif- 
ference in  rats  usually  given  as  identifying  data, 
such  as  the  number  and  location  of  the  mamm£e,  the 
variations  in  color  and  the  peculiarities  of  the  foot- 
pads, the  Javan  observers  depend  upon  the  Con- 
formation of  the  skulls  for  the  determination  of 
genera,  the  skull  of  M,  rattus  being  oval  and  arched, 
that  of  M.  decumanus  more  closely  approaching  the 
square  and  rectangular  conformation,  and  that  of 
Gunomys  being  broader,  higher  and  longer  than 
either. 

In  M.  7'attus  the  prominent  borders  which  sep- 
arate the  parietal  from  the  frontal  surfaces  of  the 
skull  are  oval;  in  M.  decumanus  they  are  parallel 
or  slightly  divergent;  in  Gunomys  they  are  lyre- 
shaped. 

M.  rattus  M.  decumanus  Gunomys 

I 


To  determine  these  differences  the  heads  of  the 
rats  are  cut  off,  the  tissues  desiccated  by  antif ormin, 
or  by  boiling  and  stripping. 

From  experiences  in  Porto  Rico,  Creel,  of  the 
U.  S.  PubHc  Health  Service,  concludes  that  M. 


102  PLAGUE 

norvegicus  {decumanus),  while  essentially  a  bur- 
rowing animal  and  not  addicted  to  climbing  or 
swimming,  is  nevertheless  quite  capable  of  doing 
either.  He  was  found  to  burrow  in  the  hardest 
earth  to  a  depth  of  two  and  one-half  feet  and  to 
pass  tlu'ough  all  kinds  of  wood,  soft  brick  and  lime 
mortar,  probably  by  gnawing. 

The  black  rat  and  Alexandrine  rat  (M.  rattus) 
in  Porto  Rico,  according  to  the  same  observer,  do 
not  burrow  at  all,  but  can  climb  and  jump  in  ex- 
pert manner,  and  are  the  species  found  in  the  rural 
districts,  remote  from  houses.  He  found  that  all 
varieties  of  rats  may  swim,  from  ships  to  the  shore, 
distances  of  from  one-fourth  to  one-half  mile,  but 
that  they  lack  the  sense  of  direction  and  probably 
do  not  land  from  ships  naturally  in  this  manner 
{Public  Health  Reports,  No.  9,  February  28, 1913) . 

The  female  decumanus  is  a  prolific  breeder  and 
brings  forth  larger  litters  than  the  WIus  rattus 
female. 

Mus  decumanus  is  generally  conceded  to  be 
larger  and  more  ferocious  than  3Ius  rattus.  For 
this  reason  he  drives  the  smaller  rats  to  the  upper 
floors,  the  decumanus  species  generally  living  near 
the  ground.    He  is  a  burrower  and  is  rarely  found 


ITS  CONTROL  AND  SUPPRESSION      103 

in  the  upper  stories  of  buildings.  Decumamis  is 
known  as  a  wharf  rat,  but  is  rarely  trapped  on  ships 
on  the  Pacific  Coast,  according  to  the  observations 
of  Surgeon  Simpson  of  the  U.  S.  Public  Health 
Service  {Public  Health  Reports,  April  11,  1913). 
According  to  the  same  observer,  Mus  rattus  is  the 
commonest  ship -borne  rat.  He  also  states  that  the 
black  rat  and  the  roof  rat  (Aleocandrinus) ,  both 
varieties  of  31.  rattus,  differ  chiefly  in  color.  They 
live  in  upper  floors,  between  ceilings,  in  walls  and 
roofs  and  are  remarkable  climbers  as  well  as  being 
expert  rope-walkers  and  wire-walkers.  On  account 
of  their  natural  wariness  and  caution  it  is  not  always 
easy  to  induce  them  to  enter  or  approach  traps. 

The  photographs  introduced  were  taken  under 
my  direction  in  Manila  in  1912,  1913  and  1914. 
Some  of  them  show  the  character  of  the  house  con- 
struction in  Tondo  District,  Manila,  where  plague 
flourished  in  1913.  Others  illustrate  methods  of 
rat-proofing  bamboo  timbers  in  houses  of  light  ma- 
terial. These  end  openings  were  either  closed  by 
introducing  cement  or  by  placing  tight-fitting  tin 
cans  over  the  ends  of  the  bamboo  rafters. 

There  are  many  interesting  memoranda,  gath- 


104  PLAGUE 

ered  and  made  in  connection  with  our  antiplague 
work  in  Manila,  especially  concerning  the  location 
and  construction  of  rat  nests  found  by  our  laborers ; 
the  materials  used  and  the  fabrication  of  the  nests. 
Memoranda  giving  details  of  rat  catching  and  rat- 
proofing  are  also  presented  and  notes  showing  the 
location  of  dead  rats  found  in  relation  to  dead  hu- 
man bodies  of  plague  victims. 

Notes  concerning  cases  of  multiple  house  in- 
fection are  also  presented  as  being  of  possible  in- 
terest. 

The  Javan  studies  in  1911  and  1912  establish 
the  fact  that  it  is  possible  to  form  a  fair  judgment 
as  to  the  length  of  time  a  rat  has  been  dead,  up  to 
ten  or  twelve  days,  from  the  condition  and  appear- 
ance of  the  rat  cadaver,  both  as  to  decomposition  and 
drying.  A  series  of  50  rats  was  studied.  It  is  to 
be  understood  that  the  conditions  under  which  these 
observations  were  made  were  tropical  conditions. 
They  would  be  fairly  comparable  with  summer  con- 
ditions in  America,  but  should  not  be  followed  too 
closely  at  other  seasons  of  the  year.  In  my  own 
experience  I  have  observed  that  ants  are  hkely  to 
attack  the  cadaver  early  and  to  obscure  the  deduc- 
tions by  their  destruction  of  the  body. 


PROGRESSIVE  POST-MORTEM  CIIAxVGES   IN  RAT  CADAVERS.      THE  XUMBERS 
INDICATE  THE  NUMBER  OF  DAYS  AFTER  DEATH 


ITS  CONTROL  AND  SUPPRESSION      105 

Dayi  after  deatb  Appearance 

First  to  third  day.  .  .  .Distention  of  the  abdomen,  in- 
creasing. 

Second  to  third  day.  .Loosening  of  hair  by  gentle  pull- 
ing. 

Third   to   fourth   day. Loosening    of    the    epidermis    by 

gentle  pulling. 

Third  to  fifth  day .  .  .  Perforation  of  abdominal  wall  with 

collapse  and  disappearance  of 
distention.  This  perforation 
may  result  from  bursting  of  ab- 
dominal wall,  or  through  anus, 
vulva  or  thorax. 

Fourth  to   sixth  day. .Moist    shrinking    of    the    body. 

Swarming  of  maggots.  Spon- 
taneous shedding  of  tufts  of 
hair. 

Fifth  to   eighth  day.  .Drying  of  body. 

Eighth  to  twelfth  day. Complete  dryness  and  rigidity. 

Photograph  (after  Publications  of  the  Civil 
Medical  Service  in  Netherlands ^  India)  shows  the 
progressive  postmortem  changes  in  rat  cadavers,  the 
numbers  indicating  the  number  of  days  after  death. 

A  Collection  of  Notes  Concerning  Rat 
Runs,  Rat  Nests,  Their  Location  and  Other 
Data. — Attention  is  invited  to  the  following  collec- 
tion of  notes  concerning  rat  runs,  rat  nests  and  their 
locations  and  other  data  collected  by  the  various 
working  parties  under  the  direction  of  Sanitary 


106  PLAGUE 

Inspectors  Brantigan,  Rentier  and  Kennard,  of 
Manila. 

Special  attention  has  been  given  to  the  finding 
and  destro}*ing  of  rat  nests,  and  in  tliis  connection 
please  note  that  during  the  month  of  ^lay,  1913, 
one  party  of  workmen  (20  men)  mider  Inspector 
Brantigan,  killed  by  hand  511  rats  out  of  a  total  of 
1319.  This  means  that  many  nests  were  broken 
up  and  that  much  breeding  was  interfered  with. 
In  June,  1918,  two  parties  (40  men)  killed  772 
rats  by  hand  out  of  a  total  of  3019. 

Tliis  work  occmTed  in  Tondo  District  in  con- 
nection with  extensive  cleaning  and  moving  oper- 
ations. 

At  1279  C.  Sandejas  -  7  rats  were  found  in 
a  nest  at  the  foot  of  a  cluster  of  bamboo  trees,  be- 
tween the  tiTinks.    Xest  was  made  of  leaves. 

At  728  C.  Velasquez,  Tondo,  12  rats  were  driven 
from  a  burrow  miderneath  a  thick  cement  floor  by 
formaldehyde  gas  delivered  in  the  burrow  tlu'ough 
a  rubber  hose.  This  burrow  was  in  sand  and  the 
rats  came  out  about  ten  minutes  after  the  flow  of 
gas  began.  All  were  killed  or  captured  and  two 
or  three  died  from  the  effects  of  the  gas. 

-  C.  is  abbreviation  for  Calle.  the  Spanish  term  for  street. 


ITS  CONTROL  AND  SUPPRESSION      107 

On  October  27,  1912,  two  of  the  rat  terriers 
belonging  to  the  Bureau  of  Health  caught  192  rats 
in  one  storeroom  at  the  ^lanila  Railway  Station,  in 
38  minutes.  At  various  times  they  have  killed  from 
10  to  25  rats  at  a  single  location,  in  connection  with 
the  cleaning  and  moving  work  done  by  the  laborers. 
The  dogs  caught  about  600  rats  in  all. 

On  March  11,  1913,  27  rats  were  caught  by 
laborers  at  202  Calle  Concha.  They  were  nesting  in 
straw  covers  which  had  been  removed  from  bottles. 

On  March  11,  1913,  13  rats  were  found  be- 
neath a  pile  of  loose  tiles  at  203  C.  Sardinas.  The 
nest  was  made  of  fibres  from  coconut  shells  and 
straw. 

On  March  13,  1913,  12  rats  were  found  among 
stones  scattered  in  a  shallow  pile  on  the  ground  at 
C.  Conservador  (interior).  Nest  was  made  of  rice 
chaff  and  small  pieces  of  cloth. 

On  March  15,  1913,  9  rats  were  caught  at  1353 
C.  Anloague  on  the  gromid  floor  beneath  a  pile 
of  boards.  Nest  was  made  of  coconut  fibre  and 
shavings. 

On  :March  16,  1913,  24  rats  were  caught  at  934 
(interior)  Velasquez  beneath  a  wood  pile.  Nest 
was  made  of  coconut- shell  fibre  and  pieces  of  cloth. 


108  PLAGUE 

On  March  17,  1913,  14  rats  were  caught  under 
a  pile  of  hay  and  straw  at  173  Velasquez.  Nest  was 
made  from  straw,  chaff  and  hay. 

The  following  articles  of  food  were  found  in 
the  above-mentioned  nests:  chicken  bones,  rice, 
coconut,  fish  and  bread. 

MEISIC  DISTRICT 

At  822  Sacristia  6  dead  rats  found  in  holes. 

At  540  T.  Alonso  a  family  of  8  rats  was  smoked 
out  and  all  were  killed. 

At  514  same  street  6  rats  were  smoked  out  and 
killed. 

At  538,  interior,  same  street,  4  rats  were  smoked 
out  and  killed. 

At  546  same  street  4  rats  were  smoked  out  and 
.killed. 

At  715  San  Bernardo  dead  rat  found  in  a  hole. 
Nest  made  of  banana  leaves  and  rags. 

At  627,  interior,  Zacateros,  9  rats  were  smoked 
out  and  killed. 

At  669  Benavides  6  rats  were  smoked  out  of 
four  nms  and  were  caught. 

At  631  Zacateros  2  rats  were  smoked  out  and 
killed. 


ITS  CONTROL  AND  SUPPRESSION      109 

At  417,  interior,  Misericordia,  4  rats  were  se- 
cured in  two  holes  under  a  tile  floor.  Many  rats 
were  caught  at  this  number  (interior)  in  traps. 

At  221  Espelita  7  rats  were  found  in  a  nest 
made  of  palm  leaves  and  excelsior;  location  of  run 
way  and  nest  beneath  tile  floor. 

At  124  Tetuan,  in  a  nest  of  straw  and  lint,  5  rats 
were  caught  by  hand,  alive. 

At  415  T.  Alonso  one  live  rat  and  3  dead  ones 
were  dug  out  from  beneath  a  tile  floor. 

SAMPOLOC  DISTRICT 

At  1001  Bilibid  Viejo  there  were  5  rat  runs, 
in  a  Chinese  store.  Eight  rats  were  secured  in  a 
nest  under  the  cement  floor.  Nest  made  of  straw 
and  paper. 

At  928  San  Sebastian  there  were  8  rat  runs.  In 
one  of  them  there  were  caught  8  rats.  The  nest 
was  made  of  straw. 

At  the  same  address,  later,  3  rats  were  caught 
in  another  run  and  8  young  rats,  with  eyes  still  un- 
opened, were  found  in  a  nest  of  straw.  A  supply 
of  bread  was  on  hand  in  this  nest. 

At  629  Tanduay  20  rats  and  nests  of  straw  and 
paper  were  found. 


110  PLAGUE 

At  the  same  address  upon  another  day  another 
rat  run  was  found  and  one  large  rat  and  16  small 
ones  were  taken  from  a  nest  made  of  rags,  straw, 
and  fibres. 

PACO  DISTRICT 

At  1115  San  Andres  in  a  Chinese  tienda  (food 
store) ,  a  long  rat  run  and  a  nest  of  rags,  straw,  and 
paper,  and  30  small  rats  were  found. 

One  nest  in  a  bamboo  tree  30  feet  above  ground 
was  found.  Rats  had  been  observed  going  up  the 
tree  and  one  was  caught  at  the  foot  of  the  tree  in  a 
trap. 

SAMPOLOC  DISTRICT 

At  629  Tanduay  14  young  rats  and  a  nest  of 
straw,  paper  and  rags  were  found  in  a  stable. 

Same  address,  later,  one  rat  run  and  nest  of 
straw  and  rags  with  one  large  rat  and  16  small  ones 
were  found. 

TONDO  DISTRICT 

March  27,  1913,  one  rat  was  caught  alive  inside 
of  a  bamboo  timber  in  house  at  51,  interior,  Pes- 
queria. 

At  631  Azcarraga  4  young  rats  were  found  in 
a  nest  of  paper,  leaves,  and  hay.  Chicken  bones, 
crab  shells,  and  rice  were  present  in  the  nest. 


ITS  CONTROL  AND  SUPPRESSION      111 

A  young  python  was  caught  in  a  lumber  yard  in 
the  Santa  Cruz  District  in  June,  1913.  In  his 
stomach  was  found  a  half-grown  rat.  Another 
snake  was  caught  in  a  rat  trap  at  the  same  addi'ess 
about  the  same  time. 

Plan  for  Household  Rat  Destruction. — 
The  following  plan  for  household  rat  destruction 
was  proposed  by  me  to  the  Director  of  Health.  It 
is  considered  worthy  of  trial  if  rat  plague  appears 
in  new  districts. 

Proposal  for  periodic  household  rat  poisoning  in 
Manila. 

Proposed  that,  upon  a  certain  day  of  each  week,  rat 
poison  be  issued  free  to  all  applicants  (householders)  in 
Manila  who  agree  to  place  same  about  their  premises, 
permitting  the  poison  to  remain  in  place  for  48  hours. 

Instructions  and  poison  placards  to  be  issued  with  the 
poison.  Issues  to  be  made  from  Station  Health  Offices  and 
records  of  issue  to  be  kept. 

Collections  of  dead  rats  to  be  made  at  the  end  of  24i 
hours  and  48  hours  by  Bureau  of  Health  employees. 
Poison  portions  to  be  collected  and  turned  in  at  the 
Station  Health  Offices  at  the  end  of  48  hours,  that  is,  at 
the  time  of  the  last  rat  collection.  Rats  to  be  tagged 
and  examined  for  plague  in  the  usual  manner. 

Due  newspaper  notice  of  the  plan  and  of  the  gratuitous 
issue  of  poison  to  be  given  to  the  people  and  their  coopera- 
tion requested. 

Plan  to  be  tested  for  at  least  two  months. 


112  PLAGUE 

MULTIPLE  HOUSE  INFECTION 
Memorandum  concerning  1364  Calle  Sande: 
Within  72  hours  (April  25-27)  five  fatal  cases 
of  plague,  all  in  Filipinos,  occm'red  in  Manila.  The 
five  deceased  persons  lived  at  334  C.  P.  Rada 
(Meisic),  1419,  interior,  C.  Dagupan,  1364  C. 
Sande  (Tondo),  642  C.  Ylala  (Meisic),  and  1492, 
interior,  C.  Dagupan  (Tondo). 

The  following  relationships  were  established  by- 
inquiry  and  investigation  and  the  circumstances 
point  strongly  to  a  common  source  of  infection  and 
to  a  single  geographic  focus  of  plague  infection  in 
connection  with  all  of  the  cases,  viz.:  at  1364  C. 
Sande  (Tondo). 

Jose  Raymundo,  boy,  aged  fifteen,  lived  at  334  C.  P. 
Rada  and  worked  daily  until  taken  sick  on  Tuesday, 
April  22,  at  1364  Sande,  in  the  shop  of  Simplicio  Enriques, 
a  silversmith,  who  lived  part  of  the  time  at  the  same 
address. 

Jose  Raymundo  died  of  bubonic  plague  at  San  Lazaro 
Hospital  on  Friday,  April  25,  1913. 

Norberta  Mendoza,  woman,  aged  fifty-six,  lived  at 
1418,  interior,  C.  Dagupan.  She  was  the  mother-in-law 
of  Simplicio  Enriques,  the  silversmith  at  1364  Sande,  and 
visited  her  son-in-law  there  frequently  and  within  a  few 
days  of  her  last  illness.  She  was  taken  sick  April  22  and 
died  at  1419,  interior,  C.  Dagupan,  on  the  morning  of 


ITS  CONTROL  AND  SUPPRESSION      113 

April  26.  At  autopsy  at  San  Lazaro  morgue,  the  same 
day,  bubonic  plague  was  found  to  be  present  and  the 
cause  of  her  death. 

Trinidad  Galves,  a  young  woman,  aged  sixteen,  lived 
at  1364  Sande  and  was  taken  sick  there  on  April  25.  She 
was  removed  to  San  Lazaro  Hospital  and  died  there 
April  26,  extensive  plague  lesions  being  found  at  autopsy. 

Pablo  Banzon,  man,  aged  twenty-six,  living  at  646 
C.  Ylaya,  was  taken  sick  on  Friday,  April  25.  He  was 
removed  to  San  Lazaro  Hospital  Saturday  afternoon 
and  died  there  Sunday  evening,  April  27.  He  was  shown 
to  have  plague  by  bacteriologic  examination  made  at  the 
Bureau  of  Science.  He  worked  at  1364  Sande  as  a  silver- 
smith, with  Jose  Raymundo  and  was  employed  by 
Simplicio  Enriques. 

Simplicio  Enriques,  aged  twenty-seven,  a  silversmith, 
conducting  his  business  at  1364  C.  Sande  and  employing 
Jose  Raymundo  and  Pablo  Banzon,  was  taken  sick  about 
April  23.  He  moved  to  two  different  houses  in  the  in- 
terval between  the  onset  of  his  sickness  and  his  transfer 
to  San  Lazaro  Hospital  on  April  27,  first  to  1419  C. 
Dagupan,  interior,  where  he  remained  until  the  death  of 
his  mother  at  this  house ;  then  to  1492  Dagupan,  interior, 
from  which  place  he  was  transferred  to  San  Lazaro  Hos- 
pital, where  he  died  with  bubonic  plague  a  few  days  later. 
Diagnosis  was  confirmed  at  autopsy. 

The  two  women  were  patients  of  Dr,  Hernando 
of  Calle  Ylaya.  He  recognized  the  case  of  the  elder 
woman  as  a  probable  case  of  plague,  after  death, 
and  reported  the  matter  to  the  Bureau  of  Health. 

The  house  at  1364  C.  Sande  is  of  the  type  in 


114  PLAGUE 

which  cases  of  rat  plague  and  hmnan  plague  have 
recently  been  found.  In  our  operations  to  put  the 
house  in  a  safe  condition  we  found  one  dead  rat, 
munimified,  in  the  basement.  Unfortunately,  the 
workmen  who  swept  it  out  did  not  note  the  exact 
location  at  which  it  was  found.  The  house  is  in  the 
midst  of  the  district  where  rat  plague  has  raged 
since  early  in  March,  1913.  The  basement  con- 
tained unauthorized  and  illegal  sleeping  rooms  until 
a  few  days  before  this  outbreak  when  they  were 
removed  in  the  course  of  our  antiplague  operations. 
The  building  is  constructed  of  bamboo  with  a  nipa 
thatch  roof. 

The  front  part  of  the  basement  was  paved,  but 
the  pavement  was  undermined  and  broken.  Being 
convinced  that  dead  plague  rats  were  present  in 
the  vicinity  of  this  house  and  probably  within  it,  I 
directed  that  the  cement  floor  under  the  silversmith 
shop  and  the  barber  shop,  located  upon  the  grotmd 
floor  at  this  address,  be  torn  up.  Accordingly,  this 
was  done  (April  28)  and  three  dead  rats  and  one 
live  one  were  found  beneath  the  cement.  As  the 
bodies  were  mmiimified  and  unfit  for  bacteriologic 
examination  they  were  burned.  The  living  rat  was 
examined  at  the  Bureau  of  Science  but  was  found 


ITS  CONTROL  AND  SUPPRESSION      115 

to  be  healthy.  The  cement  floor  was  broken  and 
permitted  fleas  from  the  dead  rats  to  enter  the  base- 
ment room  of  the  house  which  was  occupied  by  the 
silversmith  shop.  The  rats  doubtless  died  from 
plague  and  the  hungry  fleas  in  due  time  attacked 
the  nearest  persons  at  hand,  the  unfortunate  occu- 
pants of  the  silversmith  shop  and  the  two  women 
who  frequented  the  room  also. 

These  facts  account  for  the  epidemic  at  1364 
Sande  very  completely. 

The  premises  at  1364  Calle  Sande  were  quaran- 
tined by  the  following  order : 

Manila,  April  27,  1913. 

The  premises  1364  Sande  are  hereby  declared  in 
Quarantine  for  Bubonic  Plague  by  order  of  the  Director 
of  Health. 

The  inmates  will  be  permitted  to  leave  the  building 
and  find  quarters  elsewhere,  provided  they  leave  their  ad- 
dresses with  the  policeman  in  charge,  so  that  they  may  be 
readily  found.  They  must  remain  in  the  District  of  Tondo. 
If  they  remain  in  the  house  they  will  be  obliged  to  stay 
in  the  upper  story  of  the  house  and  will  have  to  arrange 
for  meals  to  be  sent  in. 

The  barber  shop  and  "  platero "  shop  are  hereby 
ordered  closed  until  further  orders. 

By  order  of  the  Director  of  Health. 

[Signed]      T.  W.  Jackson, 

Medical  Inspector,  in  Charge  of  Plague  Suppression. 


116  PLAGUE 

Memorandum  reporting  circumstance  surround- 
ing 2  cases  of  plague  at  1226  C.  Juan  Luna  (May 
17,  1913) : 

Valeriano  Lausin,.  aged  fourteen,  Filipino  male, 
Carmelo  maker  by  trade  but  out  of  work  at  time  he  was 
taken  sick,  recently  removed  to  this  house  from  917  C. 
Jaboneros  where  he  had  been  employed.  The  patient 
fixes  the  date  at  about  a  week  previous  to  his  sickness,  but 
the  proprietors  of  917  Jaboneros  are  positive  in  their 
statement  that  he  left  the  place  where  he  lived  and  worked, 
at  least  two  weeks  before.     This  boy  recovered. 

The  circumstances  and  especially  the  occuiTcnce 
of  a  second  case  at  1226  C.  Juan  Luna,  indicate 
that  infection  was  incurred  here. 

Moreover,  this  house  is  in  the  midst  of  a  rat- 
plague  infected  district. 

The  house  is  of  bamboo  and  nip  a  construction 
and  contained  illegal  basement  rooms  until  a  week 
ago.  About  60  persons  lived  in  this  house  which 
was  once  licensed  as  a  tenement  but  which  is  un- 
sanitary in  a  multitude  of  ways.  Bamboo  construc- 
tion, overcrowding,  dirty  condition  and  absence  of 
proper  drainage,  water-closet,  proper  kitchens  and 
paved  ground  floors,  together  with  bad  ventilation, 
made  it  a  dangerous  habitation  and  the  added  con- 


ITS  CONTROL  AND  SUPPRESSION       117 

dition  of  plague  infection  made  it  necessary  to 
vacate  and  quarantine  the  building. 

On  May  15,  at  the  daily  inspection  of  contacts 
in  the  house  1226  C.  Juan  Luna,  Filomena  Sunga, 
aged  nineteen,  and  a  relative  of  the  owner  of  the 
building,  was  found  to  be  sick.  Her  only  symptom 
was  fever,  but  she  was  transferred  to  San  Lazaro 
upon  suspicion  and  promptly  developed  symptoms 
of  plague.  She  died  in  a  few  days  and  the  diagnosis 
of  plague  was  verified  at  autopsy.  The  following 
order  was  issued: 

Station  "  C,"  Tondo,  Bureau  of  Health, 

Manila,  P.  I.,  May  15,  1913. 
By  order  of  the  Director  of  Health,  the  house  No.  1226 
C.  Juan  Luna  is  declared  infected  and  is  quarantined  this 
date,  for  Bubonic  Plague.  The  house  will  be  vacated  and 
a  policeman  will  register  the  names  of  all  residents  and 
the  addresses  to  which  they  remove. 

The  residents  may  remove  their  personal  effects  but 
will  not  be  permitted  to  return  while  the  quarantine  is  in 

^^^^*-  [Signed]     T.  W.  Jackson, 

Medical  Inspector,  Station  "C,"  Tondo. 

Memorandum:  Human  body  (dead  from 
plague)  and  dead  rats  found  in  the  same  basement 
room.  Upon  March  21,  1913,  a  Filipino  laborer 
living  at  140  Calle  Perla,  Tondo,  was  found  dead 
from  bubonic  plague. 


118  PLAGUE 

Upon  careful  investigation  and  search  of  the 
premises  the  following  findings  were  disclosed: 

One  rat,  large,  mummified  and  dry  and  there- 
fore dead  for  at  least  one  week,  was  found  clinging 
to  a  bamboo  wall  just  back  of  the  cot  upon  which  the 
dead  human  body  was  found. 

In  a  section  of  bamboo,  in  a  timber  constituting 
the  ceiling  of  the  basement  and  also  the  upper  part 
of  the  door  frame,  a  rat,  dead  and  dried  up,  was 
found.  This  section  was  the  end  section  of  the 
timber  which  was  partly  covered  with  nipa  thatch, 
with  which  the  sides  of  the  house  were  covered.  The 
ends  of  a  number  of  the  outside  rafters  (bamboo) 
were  found  to  be  gnawed  through. 

Similar  conditions  were  found  in  adjoining 
houses  and  in  one  case  a  live  rat  was  driven  out  of 
a  nest  in  the  bamboo. 

Sample  of  Detailed  Orders  Issued. — Sample 
of  detailed  orders  issued  by  Medical  Inspector  in 
Charge  of  Plague  Suppression.  Similar  orders 
were  issued  whenever  new  districts  were  entered  or 
new  work  undertaken. 

Memorandum  Order.    Effective  March  25,  1913: 
Beginning  to-day,  13  men  under  Assistant  Inspector 
Pards,  will  commence  cleaning  operations  at  C.   Ostra, 


BAMBOO   HOCSE  SUPPORTS  SEALED  WITH   CEMENT  TO  PREVENT  ENTRANCE  OF  RATS 
(MANILA  PLAGUE  CAMPAIGN) 


ITS  CONTROL  AND  SUPPRESSION      119 

extending  from  the  Bay  to  C.  Sande  and  will  clean  towards 
C.  Moriones.  They  will  be  provided  with  a  disinfecting 
pump  and  will  disinfect  the  ground  surfaces  wherever 
disturbed,  outdoors  and  indoors.  Cleaning  is  to  be  done 
in  the  most  thorough  manner  possible,  searching  mean- 
while for  rat  nests  and  rat  harbors ;  re-piling  wood,  tiles, 
stones  and  merchandise;  moving  all  movable  goods  out  of 
doors  in  their  search  for  rats  and  rat-holes  or  nests.  All 
goods  are  to  be  piled  above  ground  at  an  elevation  of  at 
least  one  foot.  All  bamboo  beds  and  bamboo  rafters  and 
parts  of  the  house  (in  the  basements)  made  of  bamboo  or 
of  double  walls  are  to  be  thoroughly  investigated  for  rats. 
All  foodstuff  attractive  for  rats  is  to  be  placed  in  covered 
boxes  or  galvanized  iron  cans,  tin  cans  or  barrels,  with 
tight-fitting  covers.  Special  attention  is  to  be  paid  to 
straw,  hay,  shavings,  grain,  rat-holes,  and  food. 

Two  men  will  be  detailed  to  cement  up  ends  of  bamboo 
and  rat-holes,  but  will  not  do  general  repairing.  They 
will  carry  materials  for  mixing  cement  as  needed  and  will 
not  be  wasteful  of  materials. 

If  this  force  proves  to  be  insufficient  in  numbers,  addi- 
tional men  may  be  detailed  from  the  other  working  parties. 

[Signed]      T.  W.  Jackson, 

Medical  Inspector  in  Charge  of  Plague  Suppression. 

Specimen  order  issued  to  Sanitary  Inspector 
assisting  in  Plague  Suppression  by  Medical  In- 
spector in  charge. 

Sanitary  Inspector,  Bureau  of  Health: 
Please  place  the  gang  of  workmen  under  your  charge 
in   the  square  bounded  by   Calles   Velasquez,   Moriones, 


120  PLAGUE 

Concha  and  Manila  Bay  which  is  infected  with  rat  plague. 
Treat  the  houses  and  properties  there  in  the  same  manner 
in  which  other  plague-infected  districts  have  been  treated, 
viz. :  by  policing  the  houses  and  yards,  vacating  all  base- 
ments of  light-material  houses  in  which  human  habitations 
are  illegally  present;  removing  (with  the  consent  of  the 
occupants)  all  unauthorized  basement  sleeping  places, 
beds,  platforms,  etc.,  and  other  illegal  structures,  closing 
up  the  open  ends  of  bamboo  rafters  or  timbers  of  the  house 
with  tin  or  cement. 

Where  the  occupants  resist  this  action  sanitary  orders 
should  be  issued  in  the  usual  manner  and  interference 
should  be  stopped  until  the  order  is  served  and  complied 
with.  There  are  a  number  of  most  insanitary  and  unsuit- 
able shelters  of  bamboo,  tin,  etc.,  used  for  houses  by  a 
number  of  families  in  this  square  and  it  is  desirable  to 
tear  down  these  huts  if  permission  can  be  secured.  If 
permission  is  refused  orders  should  be  issued  on  the  usual 
form. 

[Signed]     T.  W.  Jackson, 
In  Charge  of  Plague  Suppression. 

Specimen  order  issued  by  the  Medical  Inspector 
in  charge  of  Plague  Suppression. 

Station  "  C,"  Tondo,  May  21,  1913. 

Redistribution  of  rat  catchers  and  laborers  engaged  in 
antiplague  work.     Effective  May  2,  1913. 

Sanitary  Inspector  Kennard  and  20  rat  catchers  will 
move  into  Tondo  District  and  trap  and  poison  rats  in  the 
district  bounded  on  the  west  by  Manila  Bay  and  on  the 
east  by  Estero  Reina.  The  work  will  be  begun  at  the 
extreme  north  water  boundary  of  this  district  and  will 
proceed  toward  the  south. 


ITS  CONTROL  AND  SUPPRESSION      121 

Sanitary  Inspector  Brantigan  with  a  similar  number 
of  rat  catchers  (20)  will  work  within  the  same  east  and 
west  boundaries  and  will  begin  trapping  and  poisoning  at 
Calle  Moriones,  proceeding  north.  The  poisoning  and 
trapping  is  to  be  done  in  the  most  thorough  manner  pos- 
sible, as  this  is  a  dangerously  infected  district  and  rat- 
plague  must  be  controlled  and  terminated  here. 

The  laborers,  60  men,  divided  into  4  parties  of  15  men 
each  under  Assistant  Sanitary  Inspectors  Jesus,  De  la 
Rosa,  Laxamana  and  Paras,  will  continue  the  cleaning 
operations  now  under  way  on  both  sides  of  C.  Juan  Luna 
south  of  C.  Moriones  (plague  localities  in  the  same  neigh- 
borhood), and  thoroughly  disinfect. 

One  party  of  15  men  will  work  in  the  vicinity  of  C. 
Perla,  vacate  basements  as  habitations,  search  for  dead 
rats  in  yards,  houses,  bamboos,  under  broken  concrete, 
etc.,  and  will  close  up  openings  in  structural  bamboo  by 
means  of  tin  and  cement.  Emphasis  is  placed  upon  the 
necessity  for  permanently  vacating  basements  and  men 
will  be  sent  back  over  the  ground  daily  to  see  that  the 
persons  moved  out  do  not  return.  Reports  are  desired  so 
that  prosecutions  for  violations  of  the  law  may  be  insti- 
tuted if  necessary. 

[Signed]     T.  W.  Jackson, 

Medical  Inspector  in  Charge  of  Plague  ^Suppression. 

Specimen  order  issued  to  Assistants. 

May  4,  1913.     Station  "C,"  Bureau  of  Health: 
Please  place  work  parties   in    (interior)    1627—1629 
Sande  and  525  C.  Azcarraga,  to  clean,  disinfect  and  thor- 
oughly investigate  these  premises  and  the  houses,  stables 
and  other  buildings  in  the  vicinity.     Search  for  rats,  liv- 


122  PLAGUE 

ing  and  dead,  rat  nests  and  rats  in  bamboos  and  wood 
piles,  stone  piles,  stables,  under  planks  and  elsewhere. 
Cement  the  openings  in  bamboos  in  houses  or  close  with 
tin.  Make  notes  on  needed  structural  work.  Do  the  work 
as  thoroughly  as  possible. 

[Signed]     T.  W.  Jackson, 
Medical  Inspector  in  Charge  of  Plague  ^Suppression. 

Method  of  Procedure  in  Collecting  and 
Forwarding  Rats  Suspected  or  Plague  Infec- 
tion TO  THE  Laboratory  in  Manila,  P.  I. — Rat 
catching, — trapping  and  poisoning, — is  conducted 
in  accordance  with  instructions  contained  in  the 
Sanitary  Inspector's  Handbook  (pp.  36,  37,  38) 
issued  by  the  Bureau  of  Health. 

Rats  are  collected  in  Manila  and  forwarded  to 
the  Bureau  of  Science  for  autopsy  and  for  biologic 
examination  for  the  presence  of  plague  bacilli  in 
the  following  manner: 

The  various  groups  of  rat  catchers  are  provided 
with  receptacles  (iron  pails)  and  a  supply  of  a 
mixture  of  kerosene,  cresol  and  water  (kerosene 
10  parts,  cresol  2  parts;  water  88  parts). 

In  these  vessels,  filled  with  the  pulicidal  mixtm-e, 
the  rats  are  immersed,  with  a  minimum  amount  of 
handling,  as  soon  as  they  are  found  (whether  in 
traps  or  dead  from  poison). 


ITS  CONTROL  AND  SUPPRESSION       123 

If  captured  alive  they  are  killed  and  then 
promptly  immersed.  The  mixture  must  be  well 
shaken  or  stirred  when  used,  as  it  separates  upon 
standing.  The  immersion  is,  of  course,  for  the  pur- 
pose of  destroying  any  fleas  which  may  be  present 
upon  the  captured  rat. 

A  paper  tag  showing  the  date  and  the  exact 
location  of  the  place  of  capture,  with  the  name  or 
group  number  of  the  rat  catcher,  is  next  affixed  to  a 
foot  or  to  the  tail  of  the  rat  and  firmly  tied  upon 
the  same,  where  it  remains  until  the  rat  cadaver  is 
finally  disposed  of.  This  tag  is  a  card  of  strong 
Manila  paper  and  the  record  upon  it  is  made  with 
an  ordinary  lead-pencil,  as  both  ink  and  indelible 
pencil  marks  are  apt  to  become  illegible  from  wet- 
ting, whereas  lead-pencil  marks  are  little  affected 
thereby. 

If  desired,  the  disinfected  tag  in  any  given  case 
of  rat  plague  may  be  returned  to  the  Bureau  of 
Health,  for  identification,  where  an  accurate  record 
of  every  rat  captured  is  kept. 

After  dipping  and  tagging,  the  rats  are  taken 
to  a  central  point,  again  dipped,  and  placed  in  large, 
tightly-covered,  galvanized  iron  cans,  in  which  con- 
tainers they  are  delivered  to  the  laboratory  by  cart, 
once  or  twice  daily. 


124  PLAGUE 

The  Case  of  Mr.  C. — The  following  are  the 
facts  concerning  the  case  of  Mr.  W.  C,  a  prominent 
American  resident  of  INIanila  who  suffered  and  died 
from  plague  in  1914. 

Mr.  C,  an  editor,  was  taken  ill  with  plague 
on  the  night  of  September  18,  sought  medical  ad- 
vice and  entered  St.  Paul's  Hospital  September  19, 
and  was  transfen^ed  to  San  Lazaro  Hospital,  Sep- 
tember 20,  with  an  established  chnical  and  bac- 
teriologic  diagnosis  of  bubonic  plague.  He  sur- 
vived till  September  22. 

Upon  September  21,  in  the  course  of  disinfect- 
ing the  business  office  of  Mr.  C,  located  in  a  district 
which  had  furnished  a  number  of  cases  of  both  rat 
and  human  plague,  a  dead  rat,  mummified,  was 
found  in  the  right  hand  drawer  of  his  desk  and 
fleas  were  seen  to  hop  from  the  drawer  upon  open- 
ing it. 

A  flea  killed  by  the  disinfecting  mixture  at  this 
desk  was  identified  at  the  Bureau  of  Science  as  a 
rat  flea  (Xenopsylla  cheopis). 

The  rat  cadaver  was  sent  to  the  Bureau  of 
Science  and  the  following  facts  were  reported  from 
there  some  days  later: 

The  mummified  rat  and  skeleton  were  pulver- 


ITS  CONTROL  AND  SUPPRESSION      125 

ized  in  a  sterile  mortar  and  an  emulsion  was  made 
and  injected  into  guinea-pigs.  The  animals  died 
from  plague  in  a  few  days  and  plague  bacilli  were 
recovered  from  the  tissues,  as  well  as  from  the  rat 
cadaver,  by  culture. 

A  second  rat  cadaver,  found  at  the  same  time 
in  the  same  building,  dm-ing  cleaning  operations, 
was  similarly  treated  with  identical  results. 

There  could  scarcely  be  a  stronger  chain  of  con- 
dancing  evidence  against  the  rat  and  the  flea,  nor  a 
more  complete  and  convincing  explanation  of 
Mr.  C.'s  death  than  that  afforded  by  these  estab- 
lished facts  and  official  documents.  So  far  as  I 
know  there  is  no  more  striking  case  on  record  in 
the  modern  history  of  plague. 

Lettee  of  Warning  and  Appeal. — The  fol- 
lowing letter  of  warning  and  appeal  for  coopera- 
tion was  suggested  and  framed  by  me  February  10, 
1914,  at  the  time  that  extensive  rat  plague  was 
discovered  in  the  heart  of  the  business  district  of 
Manila.  I  presented  it  to  the  Director  of  Health 
with  a  strong  recommendation  for  approval  and 
publication  and  after  consideration  he  approved 
and  authorized  publication  upon  February  10.  No 
change  was  made  in  the  wording  of  the  proclama- 


126  PLAGUE 

tion,  but  it  was  issued  over  the  signature  of  the 
Director  of  Health  to  give  added  force  and  au- 
thority to  the  appeal.  The  results  were,  as  I  had 
hoped  they  might  be,  highly  beneficial.  The  tak- 
ing of  the  public  into  the  confidence  of  the  health 
authorities  brought  about  a  cooperation,  without 
which  our  efforts  in  this  difficult  situation  would 
have  been  sadly  handicapped.  It  is  my  belief  that 
this  method  should  often  be  used  by  health  author- 
ities, particularly  where  an  intelligent  community 
is  threatened. 

To  Whom  It  May  Concern  : 

You  are  hereby  informed  that  the  district  bounded  by 
Calles  Rosario,  Juan  Luna,  Dasmarinas  and  Plaza  Cal- 
4eron  (and  possibly  the  neighborhood  bordering  upon  this 
congested  district)  is  a  dangerous  one  for  all  persons  liv- 
ing or  conducting  business  therein,  on  account  of  the 
presence  there  of  extensive  rat  plague.  Six  human  cases 
(with  five  deaths)  have  recently  developed  there  and  many 
dead  rats  have  been  found.  All  human  cases  have  been 
directly  traced  to  rats  dead  from  plague. 

The  Bureau  of  Health  is  now  doing  everything  within 
its  power  to  make  this  district  safe,  but  the  attention  of 
all  citizens,  property  owners  and  tenants  is  called  to  the 
fact  that  they  are  required  by  law  to  keep  their  premises 
free  from  rats  and  to  abolish  all  structural  conditions  of 
the  buildings  which  favor  the  harboring  of  rats.  Tliis 
means  rat-proofing,  and  owners  arc  earnestly  urged  to 


ITS  CONTROL  AND  SUPPRESSION      127 

perform  this  necessary  work  now,  under  the  direction  of 
the  Bureau  of  Health. 

As  a  temporary  expedient  and  safeguard  all  interiors, 
walls,  floors  and  ceilings  should  be  sprayed  with  kerosene 
daily,  or  at  intervals  of  two  days,  to  kill  the  fleas  which 
carry  plague  from  rats  to  human  beings.  All  dark  in- 
sanitary places  used  for  living  rooms  should  be  vacated 
at  once;  all  merchandise  should  be  piled  upon  trusses  at 
least  a  foot  above  the  floor ;  all  straw,  shavings  and  other 
material  attractive  to  rats  for  nesting,  should  be  removed 
and  burned  and  all  food  materials  upon  which  rats  may 
feed  and  live  should  be  placed  in  covered  boxes,  bins  or  cans. 

All  rat-holes  should  be  permanently  closed  and  all 
broken  cement  or  masonry  should  be  repaired. 

Observance  of  these  instructions  may  save  the  lives 
of  yourselves,  your  families  and  your  tenants.  It  is  your 
duty  to  do  your  part  in  this  matter,  a  part  which  neither 
the  Bureau  of  Health  nor  the  Government  can  do  for  you. 

Through  very  great  effort  the  Bureau  of  Health  has 
controlled  plague  in  Manila  and  the  Philippine  Islands 
during  the  last  two  years. 

Residents  must  now  do  their  part,  and  owners  of 
property  must  permanently  make  their  buildings  safe  for 
tenants,  both  for  business  and  residential  purposes. 

Bacteriologic  Observations  Made  by  Dr. 
Otto  Schobl. — The  following  observations  upon 
the  bacteriologic  aspect  of  the  Manila  epidemic 
which  we  are  considering  were  made  by  Dr.  Otto 
Schobl  of  the  Biological  Laboratory  of  the  Bureau 
of  Science,  Manila,  and  pertain  to  the  cases  of  the 


128  PLAGUE 

first  year  of  the  epidemic.  They  were  printed  in 
the  December  number  of  the  Philippine  Journal  of 
Science  in  1913,  but  as  they  belong  so  definitely  to 
the  epidemic  I  am  describing  and  as  Dr.  Schobl  has 
expressed  his  willingness  for  me  to  quote  them  in 
full,  I  gladly  accept  his  permission.  Dr.  Schobl 
advanced  the  possibilities  of  blood-culture  diagno- 
sis to  such  a  point  of  rehabihty  that  it  became  prac- 
tically possible  for  us  to  expect  positive  culture  in 
nearly  every  case  of  true  plague  and  the  whole 
matter  of  bacteriologic  diagnosis  was  perfected  to 
a  high  degree  of  efiSciency  under  his  administra- 
tion of  the  laboratory  work. 

He  relates  his  observations  as  follows: 

During  the  recent  outbreak  of  plague  in  Manila,  I  had 
the  opportunity  to  make  certain  observations  ■which  are 
of  interest.  These  observations  were  made  in  the  exam- 
ination of:  (1)  Specimens  taken  from  patients  and  from 
dead  bodies  at  autopsies,  (2)  samples  of  blood-sucking 
insects  collected  in  houses  where  plague  patients  had  lived, 

(3)  rodents  caught  by  trap  or  poisoned  in  the  parts  of  the 
city  where  plague  cases  occurred  from  time  to  time,  and 

(4)  domestic  animals  suspected  of  plague  infection. 

I.  Bacteeioix)gical  Examination  of  Plague  Patients 

In  order  to  secure  as  early  diagnosis  as  possible,  the 
following  procedure  of  investigation  was  adopted: 

1.  The  bubo  was  aspirated  by  means  of  a  sterile  hypo- 


ITS  CONTROL  AND  SUPPRESSION       129 

dermic  syringe.  The  material  thus  obtained  was  placed 
in  the  water  of  condensation  of  an  agar-slant  culture  tube. 

2.  At  least  7  centimetres  of  blood  were  withdrawn 
from  the  cubital  vein  by  means  of  another  sterile  syringe, 
and  5  centimetres  of  it  were  placed  in  an  Erlenmeyer's 
flask,  containing  200  centimetres  of  neutral  meat  broth. 
The  rest  of  the  blood  was  emptied  into  a  sterile  tube,  and 
used  for  agglutination  tests. 

Cultures  obtained  by  this  method  were  examined  micro- 
scopically, and  the  growths  on  various  culture  media  were 
studied.  Gram  stain,  Loffler's  methylene  blue,  and  hang- 
ing-drop method  were  used.  Polar-staining  and  chain 
formation  in  liquid  media  and  the  characteristic  type  of 
colony  on  the  surface  of  agar  were  looked  for.  Animal 
inoculation  was  performed  in  every  case,  and  the  culture 
isolated  from  each  case  was  identified  by  agglutination 
test,  rabbit's  immune  serum  being  used. 

The  results  of  the  bacteriological  examination  of  a 
series  of  24  patients  are  tabulated  in  the  two  following 
tables.  Table  I  includes  the  fatal  cases  and  Table  II 
those  cases  which  recovered. 

The  diagnosis  of  plague  could  be  safely  made  from  the 
microscopical  examination  of  the  liquid  aspirated  from  the 
bubo  in  the  majority  of  the  cases.  However,  in  certain 
instances  the  amount  of  the  aspirated  fluid  being  small 
and  the  bacilli  very  few,  it  was  impossible  to  diagnose  the 
case,  especially  when  the  cultures  from  the  bubo  were 
negative.  Repeated  examination  of  the  patient  was  neces- 
sary under  those  conditions,  but  it  happened  in  cases  22 
and  23  that  the  patients  died  of  plague  before  a  second 
examination  could  be  made.  The  smears  and  cultures 
from  case  22  remained  sterile,  while  the  smears  and  cul- 
9 


130 


PLAGUE 


uoi^Binoo 


0000+    ooo+oooooo     ooo 


SJTl^lTlQ 


I     0000+    ooo+oooooo    ooo 


aBsrag 


0000+    ooo+oooooo     ooo 


uoi:juinoo 
-Ul'  ^Etnxnv 


+  o+ooo  000000000+  ooo 


sjnjino 


+    o+ooo     000000000+    ooo 


JB8UIg 


+  O+OOO  000000000+  ooo 


■< 

o 

■< 

% 

O 
O 


uoii 


I    lot    I    1 o  I 


ajniino 


0+00+    +++0+++0++    +00 


noiiBinoo 
-HI  '  puirav 


+  ++++0  ++00+++++0  +1  I 


8jn:nnQ 


+    ++++0     ++00+++++0     +1    I 


jBauis 


+    ++++0    ++00+++++0    +1   I 


sssnin  JO  noi;-eJiia 


■2S.2 


:^ 


O  O  O  N  10  M  t> 


?ia       edfNCCM       MNN'^COi-IWNiH-*       tSc^CO 


(TO       t^O-* 


c2oc 


o  o 


6  m> 

030 


ci  d  cJ 


O     SSSSS 


.S.S    .S    .S.S.S  0.3.3      .3.3.3 

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ITS  CONTROL  AND  SUPPRESSION      131 


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I  +0  I    I  +4-+0  I    I  +0  I       I  +0  I  +  I 


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132  PLAGUE 

tures  made  from  the  swelling  on  the  neck  of  patient  23 
revealed  the  presence  of  pneumococci.  Both  patients  died 
of  plague,  as  was  ascertained  by  examination  of  the  organs 
after  death. 

Two  of  the  patients,  cases  8  and  12,  had  numerous 
plague  bacilli  in  the  sputum  at  the  time  when  the  expec- 
toration showed  the  presence  of  blood  (twenty- three  and 
one-half  and  eighty- two  hours,  respectively,  before  death). 
In  3  cases  I  was  able  to  prove  the  presence  of  Bacillus 
pestis  in  the  skin  lesions,  intra  vitam,  fifteen,  twenty-two, 
and  forty-eight  hours,  respectively,  before  death.  In  case 
18  there  was  no  doubt  that  the  skin  lesions,  which  cov- 
ered the  whole  body  and  the  face,  were  of  secondary 
nature,  as  the  patient  died  shortly  afterward.  It  was 
undoubtedly  a  case  similar  to  those  reported  by  Gotschlich 
and  Zabolotny.^  In  the  other  two  patients  there  was 
only  1  maculopapulous  efflorescence  on  the  foot  in  case  1 
(with  a  corresponding  femoral  bubo)  and  2  lesions  of  the 
same  type  on  the  arm  and  forearm  in  case  4  (with  a  cor- 
responding axillary  bubo).  It  is  possible  that  these 
lesions  were  the  original  port  of  entry  of  infection.  Num- 
erous plague  bacilli  were  found  in  the  skin  lesions  of  these 
cases,  both  microscopically  and  in  culture. 

The  plague  patients  tabulated  in  Table  II  recovered. 
They  were  all  treated  with  antiplague  serum'.  While 
cases  5,  2,  19,  and  24*  appeared  cKnically  to  be  rather 
severe,  cases  2  and  20  were  mild. 

It  can  be  seen  from  the  table  that  the  plague  bacilli 
may  not  be  detected  in  the  enlarged  gland  at  first  (  case  2  ) 
and  that  their  presence  may  be  revealed  only  after  re- 

^  KoUe    und    Wassermann :     Handbuch    der    pathogenen 
Mikroorganismen.    Gustav  Fischer,  Jena  (1903)  2,  521. 


ITS  CONTROL  AND  SUPPRESSION      133 

peated  examination  of  the  bubo.  It  is  also  evident  from 
the  results  of  repeated  examinations  that  the  pla,gue  bacilli 
disappear  from  the  infected  gland  in  a  comparatively 
short  time,  as  a  rule  at  the  time  when  pus  starts  to  form. 
Contrary  to  the  findings  in  patients  who  died,  distinct 
phagocytosis  was  noticed  in  the  smears  made  from  the 
aspirated  liquid  in  those  patients  who  recovered  and  who 
had  been  treated  with  serum  soon  after  the  onset  of  the 
disease.  It  is  undoubtedly  tl^iis  process  that  clears  the 
gland  of  the  infectious  agents. 

The  general  opinion  in  regard  to  the  presence  of  BacU- 
lus  pestis  in  the  circulating  blood  seems  to  have  been,  as 
Thompson  remarks,  that  '"  the  bacillus  is  rarely  to  be 
found  in  the  peripheral  blood  stream  before  the  agonal 
stage."  ^ 

The  Austrian  Commission,  using  few  drops  of  blood, 
found  positive  blood  culture  in  40  per  cent ;  Calvert  in 
Manila  in  100  per  cent  when  examined  twenty-four  ?iour3 
before  death ;  Choksy,  Berestneff.  and  Mayr  in  45  per 
cent ;  and  Greig  in  60  per  cent.  The  Indian  Commission 
examined  28  patients,  and  obtained  positive  blood  cul- 
tures in  16  out  of  23  fatal  cases.  Not  a  single  positive 
blood  culture  was  obtained  from  the  patients  who  sur- 
vived. The  time  of  blood  examination  in  positive  cases 
was  three  and  one-half  to  seventy-five  and  one-half  hours 
before  death.  The  amount  of  blood  used  was  1  cubic 
centimetre.  Only  6  out  of  the  SO  samples,  which  gave 
positive  blood  culture,  were  found  positive  by  microscopical 
examination  of  blood  smears.  The  following  conclusions 
are  based  on  these  observations  in  regard  to  the  septicEemic 
stage  of  bubonic  plague:  (1)   *'A  severe  septicaemia  may 

*  Journ,  Hyg.j  Cambridge  (1906)^  6,   558. 


134  PLAGUE 

be  present  at  a  comparatively  early  stage  of  the  disease 
and  for  a  considerable  number  of  hours  before  death,  and 
(2)  the  septicaemia  may  be  of  an  irregular  and  fluctuating 
type."  5 

From  the  tables  it  will  be  seen  that  out  of  15  patients 
examined  by  me,  14;  gave  positive  blood  culture;  and  of 
these  3  recovered.  One  blood  culture  revealed  the  pres- 
ence of  streptococcus  in  addition  to  Bacillus  pestis.  The 
results  of  the  examinations  tabulated  in  Tables  I  and  II 
show,  in  agreement  with  the  findings  of  the  Indian  Com- 
mission, the  occasional  early  occurrence  of  plague  bacilli 
in  the  blood  stream,  as  the  time  of  examination  in  the 
positive  cases  varied  from  one  hour  to  one  hundred  six 
hours  before  death.  In  consideration  of  the  ephemeral 
character  of  the  septicemic  stage  of  plague,  as  evidenced 
by  repeated  blood  cultures  in  the  three  patients  who  re- 
covered, one  can  hardly  avoid  the  impression  that  there 
is  a  certain  degree  of  septicaemia  in  every  case  of  plague. 
The  possibility  of  detecting  the  bacillus  in  the  circulat- 
ing blood  increases  in  proportion  with  the  quantity  of 
blood  used  for  culture.  The  best  chance  to  recover  plague 
bacilli  from  the  circulating  blood  seems  to  be  in  the  stage 
of  high  fever  and  general  prostration. 

The  phenomenon  of  agglutination  of  plague  bacilli  by 
the  serum  of  patients  was  first  observed  by  Wissokowitsch 
and  Zabolotny  in  1897  ^  and  later  confinned  by  the  Ger- 
man Plague  Commission.  Vagedes,  Klein,  and  others  ° 
pointed  out  the  defects  of  the  reaction  as  a  diagnostic 

^  Ibid.  (1907),  7,  395. 

"  Referred  to  in  Kolle  und  Wassermann :    Handbuch  der 
pathogenen  Mikroorganismen  (1903),  2,  524. 


ITS  CONTROL  AND  SUPPRESSION      135 

means.  Aside  from  the  technical  difficulties,  the  reaction 
was  found  inconstant,  and  its  occurrence  was  not  noticed 
until  the  second  week  of  the  disease  and  even  then  only 
in  low  dilutions  of  the  serum. 

Although  the  recent  work  of  Strong"^  and  of  Strong 
and  Teague  *  has  reduced  the  technical  difficulties,  the 
fact  remains  that  positive  agglutination  of  plague  bacilli 
by  the  patient's  serum  cannot  be  obtained  in  the  first  week 
of  the  disease,  and,  therefore,  the  isolation  of  plague 
bacilli  from  the  body  of  the  patient  is  still  the  only  quick 
and  safe  method  of  plague  diagnosis. 

Having  utilized  the  technic  devised  by  Teague,  I  have 
had  no  difficulty  in  performing  the  agglutination  test  in 
plague.  The  emulsion  of  plague  bacilli,  to  be  used  for 
the  test,  was  prepared  by  suspending  young  cultures  of 
virulent  plague  bacilli,  grown  at  30°  C,  in  salt  solution 
and  filtering  the  suspension  through  filter  paper.  No 
antiseptic  was  added  nor  heat  applied.  Serial  dilutions 
of  unheated  patient's  serum  were  mixed  with  equal  amounts 
of  bacterial  suspension  in  small  test  tubes.  Incubation 
at  35°  C.  followed.  Controls,  consisting  of  serial  dilutions 
of  normal  human  serum  as  well  as  bacterial  suspensions 
without  serum,  excluded  any  possible  error  which  might 
have  been  caused  by  spontaneous  sedimentation  of  the 
bacterial  suspension ;  while  a  parallel  test  with  highly 
agglutinant  serum  facilitated  the  reading  of  positive 
results. 

Altogether,  22  tests  were  performed  on  15  patients, 
11  of  whom  were  fatal  cases  and  4  of  whom  recovered. 

"^  The  Philippine  Journal  of  Science,  Sec.  B.  (1907),  2, 
155. 

«  Ibid.  (1912),  7,  194-201. 


136  PLAGUE 

In  the  negative  reactions,  the  duration  of  the  disease  at 
the  time  of  examination  ranges  from  two  to  six  days. 
The  non-fatal  cases  showed  slight  agglutination  from  the 
sixth  day  on.  From  that  day,  the  agglutination  titer  of  the 
serum  was  found  to  rise,  and  the  agglutinins  persisted  in 
the  blood  of  convalescents  up  to  the  seventh  week  of  the 
disease.^ 

It  must  be  borne  in  mind  that  the  patients,  who  showed 
positive  agglutination,  had  been  vigorously  treated  with 
antiplague  serum.  Nevertheless,  in  consideration  of  the 
low  titer  of  the  curative  serum  (dilution  1 :  32,  agglutina- 
tion positive;  dilution  1:  64,  agglutination  negative),  the 
rise  of  the  agglutinant  power  of  the  patient's  serum  in 
dilutions  higher  than  1 :  16  cannot  be  explained  as  wholly 
due  to  passive  immunity,  but  rather  to  active  immunity 
arrived  at  on  the  principle  of  simultaneous  immunization. 

From  the  preceding  observations  the  following  con- 
clusions are  drawn: 

1.  The  importance  of  blood  cultures  as  a  diagnostic 
means  is  evident  from  the  fact  that  positive  blood  culture 
was  obtained  in  practically  every  case  that  was  examined 
in  the  febrile  stage  of  the  disease,  even  when  buboes  or 
signs  of  pulmonary  involvement  had  not  been  detected 
clinically. 

2.  It  is  also  evident  that  Bacillus  pestis  may  be  found 
in  the  circulating  blood  of  the  patients  even  in  cases  which 
subsequently  recover. 

3.  The  period  of  time  during  which  Bacillus  pestis 
circulates  in  the  blood  is  evidently  short  and  irregular. 

"  It  is  hoped  that  it  will  be  possible  to  examine  some  of  the 
survivors  for  agglutination  from  time  to  time. 


ITS  CONTROL  AND  SUPPRESSION      137 

4.  Mixed  infection  may  be  encountered  in  plague  sep- 
ticaemia {Streptococcus,  Pneumococcus) . 

5.  The  agglutination  test  is  of  no  value  for  the  diag- 
nosis of  plague,  as  it  was  found  positive  only  in  con- 
valescents. 

6.  Phagocytosis  of  plague  bacilli  in  the  bubo  was 
noticed  only  in  patients  who  recovered  after  being  vigor- 
ously treated  with  curative  serum. 

7.  The  presence  of  numerous  plague  bacilli  in  com- 
paratively insignificant  skin  lesions  during  the  life  of  the 
patient  points  to  the  possibility  of  direct  transmission, 
while  the  fact  that  a  patient  without  any  apparent  bubo, 
who  is  not  so  sick  as  to  be  detained  from  his  daily  occupa- 
tion, may  expectorate  large  numbers  of  plague  bacilli,  are 
facts  of  great  importance  with  regard  to  the  communica- 
tion of  the  disease.  It  is  obvious  that  the  last-mentioned 
condition  might,  and  very  likely  does,  give  rise  to  an  epi- 
demic of  pneumonic  plague  if  the  atmospheric  and  sanitary 
conditions  are  favorable. 

II.  Observations  on  the  Transmission  of  Plague  by 
Blood-sucking  Insects 

Judging  from  the  data  which  have  been  collected  from 
the  literature  ^^  on  the  transmission  of  plague  (Table  III), 
Simond  seems  to  have  been  the  first  to  call  attention  to 

^^  Centralbl.  f.  Backt.,  1  Abt.  (1897),  22,  87,  437.  Re- 
port of  Indian  Plague  Commission  (1898-99).  Zeitschr.  f. 
Hyg.  u.  Infectionskrankh.  (1901)^  36,  89.  KoUe  imd  Wasser- 
mann:  Handbuch  der  pathogenen  Mikroorganismen  (1903),  2, 
538.  Zeitschr.  f.  Hyg.  u.  Infectionskrankh.  (1905),  51,  368. 
Journ.  Hyg.,  Cambridge  (1907-10),  plague  numbers.  Ibid. 
(1908),  8,  162,  260. 


138 


PLAGUE 


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ITS  CONTROL  AND  SUPPRESSION      139 

the  important  part  which  blood-sucking  insects,  particu- 
larly fleas,  play  in  the  transmission  of  plague.  Although 
many  investigators  have  been  successful  in  demonstrating 
the  presence  of  Bacillus  pestis  in  the  digestive  system  of 
blood-sucking  insects,  it  was  not  until  the  experiments  of 
Gauthier  and  Raybaud  that  the  actual  transmission  of 
plague  infection  by  fleas  was  convincingly  proved.  Ever 
since  the  exhaustive  and  conclusive  experiments,  which 
were  carried  out  both  under  natural  and  artificial  con- 
ditions by  the  British  Plague  Commission,  and  the  work  of 
Verbijtski,  which  antedates  the  British  Commission,  were 
presented,  there  has  been  no  doubt  that  the  transmission 
of  plague  by  blood-sucking  insects,  particularly  by  the 
fleas,  is  one,  although  not  the  only,  mode  of  spreading  this 
disease.  It  is  obvious,  as  Herzog  correctly  remarks,  that 
the  factors  which  are  responsible  for  the  spreading  of 
plague  must  be  considered  individually  in  each  epidemic 
and  in  various  parts  of  the  world  as  well.  There  is  no 
doubt  that  the  importance  of  any  insect  in  the  trans- 
mission of  plague  depends  on  its  habits  as  well  as  on  those 
of  the  host,  be  it  either  animal  or  man. 

During  the  recent  outbreak  of  plague  in  Manila,  sev- 
eral samples  of  bed-bugs  from  the  beds  of  the  plague  pa- 
tients and  dog  fleas  from  a  plagueinfected  house  were 
collected  and  examined,  but  with  negative  result. 

In  spite  of  the  fact  that  it  adds  nothing  new  to  the 
question  of  whether  or  not  plague  can  be  transmitted  by 
fleas,  since  the  question  has  been  conclusively  answered 
by  the  work  of  the  Indian  Commission,  nevertheless  the 
following  observations  of  a  small  outbreak  of  plague  among 
animals,  the  spreading  of  which  was  due  solely  to  fleas,  are 
of  interest. 

One  wild  rat  was  inoculated  with  strain  Iloilo  3  of 


140  PLAGUE 

Bacillus  pestis.  The  skin  adjoining  the  root  of  the  right 
ear  was  scarified,  and  a  loopful  of  the  culture  was  smeared 
on  the  scarified  skin.  The  rat  was  found  dead  three  days 
after  the  inoculation. 

The  cage  containing  the  dead  rat  was  immersed  in 
kreolin  solution.  At  autopsy  the  cervical  glands  were 
found  slightly  swollen,  somewhat  reddened,  but  no  haemor- 
rhagic  oedema  of  the  surrounding  tissue  was  noticeable. 
There  was  slight  necrosis  at  the  place  of  inoculation,  show- 
ing superficial,  purulent  discharge.  Clear  effusion  in  both 
pleural  cavities  and  one  hemorrhage  in  the  pleura  were 
found.  The  lungs  were  hypersemic,  but  otherwise  normal. 
The  spleen  was  of  somewhat  darker  color,  but  otherwise 
normal  in  size  and  appearance.  The  liver  showed  a  slight 
degree  of  parenchymatous  degeneration,  the  congestion 
making  prominent  the  structure  of  the  organ.  The  typ- 
ical, although  not  constant,  changes  of  the  organ,  which 
are  characteristic  of  natural  plague  infection  in  rats,  were 
absent.  The  kidneys  were  without  macroscopic  change. 
The  lymph  glands,  with  exception  of  the  cervical  nodes, 
were  normal. 

Examination  of  the  rat's  fur  revealed  ectoparasites 
on  the  neck,  under  the  chin,  and  back  of  the  ears ;  these 
at  the  time  of  the  examination  apparently  were  dead. 
About  6  common  rat  fleas  were  found  and  identified  as 
Lcemopsylla  cheopis  Rothsch.  The  parasites  were  im- 
mersed in  sterile  salt  solution  for  three  hours.  When  re- 
moved in  a  dry  test  tube,  they  began  to  move  about  slug- 
gishly.   The  intestinal  tract  of  these  fleas  contained  blood. 

Five  of  the  fleas  were  crushed  by  means  of  sterile 
forceps,  and  inserted  in  a  pocket  under  the  shaved  skin 
of  a  guinea-pig.  The  animal  died  of  plague  within  three 
days,  showing  considerable  hemorrhagic   oedema   around 


ITS  CONTROL  AND  SUPPRESSION      141 

the  place  of  inoculation,  typical  bilateral  inguinal  buboes, 
and  characteristic  changes  in  the  spleen.  Smears  and 
cultures  made  from  the  bubo  and  spleen  were  positive  for 
Bacillus  pestis. 

Another  wild  rat,  which  was  in  a  separate  cage  in  the 
same  room  where  rat  1  had  been  kept,  died  twenty-four 
hours  after  rat  1.  The  two  cages  were  at  least  10  centi- 
metres apart.  Rat  2  harbored  fleas  of  the  same  species 
as  were  found  on  rat  1. 

Numerous  severe  bites  were  detected  back  of  the  ears 
and  on  the  neck  of  the  dead  animal.  The  post-mortem 
findings  were  identical  with  those  described  in  rat  1 ;  that 
is,  cervix^al  buboes,  pleural  effusion,  and  slightly  enlarged 
spleen. 

It  is  well  to  remark  that  both  rats  had  been  kept  in  the 
same  room  for  about  six  months.  Fleas  had  never  been 
noticed  on  our  guinea-pigs.  During  the  time  the  rats  had 
been  kept  in  the  plague  house  no  irregular  results  were 
noticed  in  plague-inoculated  animals.  At  the  time  the 
first  rat  was  inoculated  no  other  plague-infected  animals 
were  in  the  plague  house,  and  since  that  time  another  build- 
ing has  been  used  for  plague-infected  animals. 

Two  days  after  the  death  of  rat  2  three  guinea-pigs, 
which  were  kept  in  separate  cages  in  the  same  room,  were 
found  dead  of  plague  (smears  and  cultures  were  both 
positive).  Several  fleas  {Loemopsylla  cheopis)  were  found 
on  the  necks  of  these  animals.  They  were  collected  and 
inoculated  in  the  same  way  as  the  fleas  from  the  first  rat. 
The  experimental  animal,  which  was  inoculated  with  the 
fleas,  was  killed  and  found  to  be  infected  with  plague. 
The  findings  were  local  reaction,  inguinal  buboes,  and 
typical  spleen.  Smears  and  cultures  were  positive  for 
Bacillus  pestis. 


142  PLAGUE 

Although  numerous  healthy  guinea-pigs  were  ex- 
amined in  the  same  plague  house,  no  fleas  could  be  found 
at  that  time,  only  the  2  rats  and  the  first  3  guinea-pigs 
are  positively  known  to  have  harbored  fleas,  the  latter 
after  the  death  of  the  rats  and  not  before. 

The  gross  lesions  in  these  naturally  infected  guinea- 
pigs  were  somewhat  unlike  those  found  in  guinea-pigs  in- 
fected either  by  vaccination  or  by  intraperitoneal  or  sub- 
cutaneous inoculation.  All  except  one  showed  primary 
buboes  on  the  neck  with  more  or  less  extensive  hemorrhagic 
oedema  extending  in  some  cases  over  the  thorax.  There 
was  little  pleural  effusion  present;  the  spleen  always 
showed  typical  changes  of  necrotic  foci  varying  in  size 
and  number.  In  one  instance  similar  foci  were  found  also 
in  the  liver,  large  enough  to  be  visible  macroscopically. 
This  was  in  a  case  where  like  changes  were  found  in  the 
lungs. 

Only  one  of  the  guinea-pigs  showed  an  exception,  in 
that  the  primary  buboes  were  located  in  the  inguinal 
region,  with  pelvic  and  axillary  glands  secondarily  in- 
volved. These  are  the  findings  usually  met  with  in  guinea- 
pigs  artificially  infected  with  plague  by  the  vaccination 
method,  if  the  lower  part  of  the  abdomen  be  chosen  for 
inoculation.  The  reason  for  such  a  deviation  from  the 
findings  in  the  rest  of  the  guinea-pigs  may  lie  in  the  fact 
that  this  animal  was  almost  completely  deprived  of  hair 
by  a  skin  disease. 

It  is  of  importance  to  mention  the  skin  lesions  which 
were  found  on  the  necks  of  the  guinea-pigs,  particularly 
under  the  chin.  Besides  small  red  spots  which  appeared 
to  be  fresh  flea  bites,  small,  elevated,  and  fairly  deep  in- 
filtrations partly  covered  with  moist  scab  were  found  in 
the  skin  under  the  chin.     Other  animals  showed  changes 


ITS  CONTROL  AND  SUPPRESSION      143 

usually  found  in  the  scarified  skin  of  guinea-pigs  after 
artificial  inoculation  with  plague  material.  The  base  of 
each  cutaneous  efilorescence  was  hemorrhagic  and  (Ede- 
matous. 

A  histological  study  of  the  tissues  of  these  guinea-pigs 
known  to  be  naturally  infected  by  plague  fleas  showed  the 
following  changes : 

The  Cervical  Bvbo. — The  enlarged  lymphatic  gland 
was  surrounded  with  a  thickened  capsule.  Necrosis  ex- 
isted in  the  subcapsular  part  of  the  gland,  where  it  formed 
an  almost  continuous  circular  zone,  leaving  the  central 
part  less  changed.  Smaller  irregular  necrotic  foci  were 
scattered  throughout  the  section.  Polymorphonuclears  in 
various  stages  of  disintegration  were  found  throughout  the 
section. 

The  Lungs. — Very  few  blood  extravasations  were  pres- 
ent in  the  alveoli;  otherwise  normal. 

The  Spleen. — The  capsule  was  thin.  There  were  sub- 
capsular hemorrhages.  The  Malpighian  bodies  were 
somewhat  enlarged,  but  of  normal  structure.  Throughout 
the  parenchyma  irregiilar  multiple  necrotic  foci  were 
found,  leaving  but  little  of  spleen  tissue  intact.  Numer- 
ous polymorphonuclears  which  were  present  showed  vary- 
ing degrees  of  karyorrhexis. 

The  Kidneys. — The  outline  of  the  cells  was  indefinite ; 
a  few  miliary  hemorrhages  existed  in  the  cortical  part  of 
the  organ. 

The  Liver. — There  was  excessive  congestion,  fatty  de- 
generation, and  pigmentation  of  the  cells.  The  capsule 
was  slightly  thickened. 

The  Skin. — The  epithelium  was  missing  in  one  place 
in  the  section,  and  cellular  infiltration  extended  from  that 
place  into  the  subepithelial  layer  of  the  surrounding  skin. 


144  PLAGUE 

The  same  kind  of  infiltration  reached  deep  into  the  skin, 
stripes  of  cellular  infiltration  penetrating  into  the  tissue 
along  the  muscle  fibres.  There  was  no  direct  connection 
between  the  cellular  infiltration  and  the  follicles  of  the 
hair. 

It  may  be  well  to  describe  in  detail  the  time  of  death 
from  plague  among  these  and  the  other  animals  in  this  out- 
break, as  well  as  the  time  when  the  plague  house  was 
disinfected. 

The  first  animal  (rat  1)  having  been  inoculated  on 
August  27,  in  the  afternoon,  died  of  plague  within  three 
days  (August  30).  The  second  animal  (rat  2)  died 
twenty-four  hours  later.  Guinea-pigs  S,  4,  and  5  (see 
plan)  were  found  dead  on  the  morning  of  September  2; 
that  is,  two  days  after  the  death  of  rat  2  and  three  days 
after  the  death  of  rat  1. 

The  same  day  that  the  three  guinea-pigs  were  found 
dead  of  plague,  rooms  I,  III,  IV,  and  VI  were  thoroughly 
disinfected.  The  floor,  the  ceiling,  and  the  walls  were 
sprayed  with  kerosene  and  lysol  solution.  The  remaining 
animals  in  room  VI  were  destroyed,  and  the  cages  disin- 
fected. No  animals  were  kept  in  rooms  I,  III,  and  IV  at 
that  time. 

Three  days  after  the  death  of  animal  5,  guinea-pigs 
6  and  7  were  found  dead  of  plague,  while  the  next  day 
guinea-pigs  8  and  9  died.  No  death  occurred  on  Septem- 
ber 7,  but  the  next  two  days  each  recorded  two  plague 
guinea-pigs  (10,  11,  12,  and  13).  On  September  11,  the 
last  guinea-pig  died  of  plague  in  this  outbreak.  The 
whole  building  was  then  thoroughly  disinfected.  No 
plague-inoculated  animals  were  kept  in  the  rooms  after 
the  first  sign  of  the  epidemic.  After  September  11,  no 
more  cases  of  spontaneous  plague  infection  were  observed. 


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ITS  CONTROL  AND  SUPPRESSION       145 

It  will  be  noticed  that  the  epidemic  lasted  eleven  days 
after  the  first  animal  died  and  fourteen  days  after  animal  1 
was  inoculated.  Altogether,  14j  animals  out  of  at  least 
200  animals  exposed  died  of  plague. 

No  death  occurred  among  rabbits,  although  these 
animals  were  distributed  among  the  guinea-pigs.  In  fact, 
2  rabbits  were  surrounded  by  plague  guinea-pigs  8,  9, 
and  10,  but  did  not  contract  plague. 

From  the  epidemiological  -standpoint  it  is  interesting 
to  know  the  dimensions  and  location  of  the  cages  in  which 
the  animals  were  kept. 

Aside  from  the  2  rats  which  were  confined  in  ordinary 
traps  that  stood  on  a  table  80  centimetres  high,  the  rest 
of  the  animals  were  kept  in  regular  metal  animal  cages. 
The  dimensions  of  the  cages  are:  Fifty  centimetres  long, 
36  centimetres  broad,  and  30  centimetres  high.  The  cage 
stands  on  four  legs  each  10  centimetres  long;  the  centre 
of  the  b^  .tom  of  the  cage  holds  a  drain  opening  8  centi- 
metres above  the  floor. 

The  majority  of  the  cages  in  room  II  were  located 
on  the  floor ;  some  on  the  second  shelf  of  a  wooden  rack. 
This  last-mentioned  arrangement,  judging  from  the  con- 
struction of  the  wooden  frame,  allowed  a  continuous  pas- 
sageway for  the  fleas  to  the  second  shelf  of  the  racks. 
On  the  other  hand,  the  deaths  among  the  guinea-pigs  in 
room  V  were  restricted  to  the  cages  standing  on  the  floor, 
the  majority  of  cages  in  that  room  being  placed  on  tables 
80  centimetres  high. 

Only  a  theoretical  explanation  can  be  given  of  the  short 
duration  and  sudden  cessation  of  the  outbreak.  One  can 
assume  with  great  probabiHty  that  the  first  partial  dis- 
infection drove  the  fleas  away  from  the  primary  source 
of  infection,  and  that  they  traveled  as  far  as  possible. 
10 


146  PLAGUE 

The}^  finally  settled  in  those  guinea-pig  cages  which  had 
not  been  molested  by  the  first  disinfection.  Having  no 
new  supply  of  plague  blood  (all  of  the  plague-infected 
guinea-pigs  having  been  removed,  most  of  them  before 
death),  the  fleas  soon  cleared  themselves  of  plague  bacilli. 
The  peculiar  feature  of  the  outbreak,  namely,  the  failure 
to  find  fleas  on  the  animals  in  rooms  II  and  V,  finds  its 
explanation  in  the  observation  of  the  Indian  Commission 
who  found  that  the  fleas  "  died  or  disappeared  very 
rapidly." 

The  following  conclusions  can  be  drawn  from  these 
observations : 

1.  The  common  rat  flea  {Loemopsylla  cheopis)  pre- 
fers the  rat  to  the  guinea-pig. 

2.  In  the  absence  of  rats  it  will  attack  guinea-pigs 
rather  than  rabbits, 

3.  The  fleas  which  have  sucked  blood  from  rats  or 
guinea-pigs  afflicted  with  plague  septicaemia  were  found  to 
harbor  virulent  plague  bacilli  inside  of  their  bodies. 

4.  The  transmission  of  plague  infection  by  direct  or 
indirect  contact  being  excluded  in  our  case,  the  fact  that 
fleas  of  the  same  species  and  harboring  plague  bacilli  were 
found  on  the  rat  and  on  the  guinea-pigs,  the  presence  of 
flea  bites  on  the  rats  and  on  the  guinea-pigs  with  positive 
findings  of  skin  lesions  on  that  part  of  the  body  where  the 
fleas  and  flea  bites  were  located,  together  with  the  anatom- 
ical picture  of  the  findings  in  the  guinea-pigs,  lead  to  but 
one  explanation ;  namely,  that  the  plague  infection  was 
transmitted  by  fleas. 

III.  Obsekvations  on  Animals  Suspected  of  Plague 

Out  of  the  several  tens  of  thousands  of  rodents  ex- 
amined during  the  antirat  campaign,  we  have  found  only 


ITS  CONTROL  AND  SUPPRESSION      147 

two  plague  rats  which  showed  the  typical  picture  of 
natural  plague  infection  in  rat;  that  is,  cervical  buboes 
with  surrounding  oedema,  subcutaneous  injection,  pleural 
eifusion,  enlarged  spleen,  and  such  changes  of  the  liver  as 
are  characteristic  of  natural  plague  infection  in  rats. 
Microscopically,  large  numbers  of  plague  bacilli  were 
found  in  these  cases,  and  pure  cultures  of  Bacillus  pestis 
were  recovered  from  the  spleen.  Histological  examination 
of  internal  organs,  particularly  that  of  the  liver,  con- 
firmed the  bacteriological  findings.  The  remainder  of  the 
plague  rats  exhibited  only  two  of  the  signs  of  plague 
infection,  namely,  bubo  and  oedema  of  the  surrounding 
tissue,.and  eventually  hemorrhages. 

Besides  plague  infection,  a  great  number  of  rats 
showed  purulent  conditions  from  causes  other  than  plague. 
Abscesses  of  the  lungs  were  frequently  met  with,  and  cer- 
vical or  axillary  buboes  are  not  uncommon  in  Manila  rats. 
Various  pyogenic  bacteria  were  found  in  the  pus  of  such 
abscesses.  Of  the  less  common  was  Bacillus  pyocyaneus 
and  the  pneumobacillus  of  Friedlander.  Chronic  plague 
was  excluded  in  these  cases  since  the  animal  inoculation 
failed  to  produce  plague  infection. 

More  than  half  of  the  rats  examined  harbored  para- 
sites in  their  organs.  EcJiino coccus  teniceformis  was 
found  in  the  liver  of  practically  every  gray  rat,  while  a 
small  Ascaris  and  Tcenia  diminuta  were  not  uncommon  in 
the  intestines.  Two  rats  were  found  to  have  sarcosporidi- 
osis,  2.6  per  cent,  showed  rat  leprosy,  and  7.4  per  cent, 
trypanosomiasis.  One  tumor  of  the  mammary  gland  and 
one  tumor  in  the  axillary  region  were  encountered,  while 
one  tumor  of  the  large  curvature  of  the  stomach  proved 
to  be  a  chronic  inflammatory  tumor  due  to  parasites.  One 
peritoneal  tumor  in  a  rat  (Mus  decumanus)  gave  the  im- 


148  PLAGUE 

pression  of  a  malignant  tumor  on  account  of  the  miliary 
dissemination  of  the  peritoneum.  It  was  found  to  consist 
of  muscle  and  spindle-cell  sarcomatous  tissue.  Ectopara- 
sites were  very  seldom  noticed,  on  account  of  the  method 
of  collecting  the  rats.  When  present,  they  were  mites 
and  fleas. 

In  the  naturally  infected  plague  rats  the  rigidity  of 
the  fresh  cadaver  was  pronounced.  The  primary  bubo 
was  in  every  case  cervical.  Cervical  glands  were  enlarged 
and  hemorrhagic  with  sHght  oedema  of  the  surrounding 
tissue.  The  subcutaneous  injection  extended  over  the 
neck  and  chest.  The  inguinal  glands  were  small  and  pig- 
mented. The  lungs  were  collapsed,  and  showed  hemor- 
rhagic foci.  The  spleen  was  slightly  enlarged,  firm,  and 
dark  red.  The  liver  was  rather  large,  firm,  pale  red, 
with  shade  of  yellow,  which  was  caused  by  minute  yellow- 
ish foci  thickly  scattered  throughout  the  tissue  and  visible 
through  the  capsule.  The  kidneys  were  hypersemic.  The 
intestiries  were  without  change.  The  serous  membranes 
were  pale  with  no  hemorrhages. 

Histological  examination  of  the  tissue  of  naturally 
infected  plague  rats  showed  the  following  changes : 

Liver. — The  structure  of  the  organ  was  well  marked; 
the  veins  dilated,  trabeculse  slightly  compressed,  nuclei 
well  stained,  and  few  of  the  liver  cells  showed  vacuoles. 
Small  foci,  most  numerous  under  Glisson's  capsule,  were 
scattered  throughout  the  organ ;  they  varied  in  size,  but 
were  not  larger  than  a  miliary  tubercle.  The  small  ne- 
crotic foci  were  found  to  consist  of  few  necrotic  liver  cells. 
The  centre  of  the  larger  foci  was  formed  by  degenerated 
and  necrotic  liver  tissue,  surrounded  by  round-cell  infil- 
tration. Polymorphonuclears  were  also  found  in  the  zone 
of    cellular    infiltration.      There   was    a    slight    degree    of 


ITS  CONTROL  AND  SUPPRESSION      149 

hemorrhage  in  each  focus.  Epithelioid  cells  and  large 
vesicular  cells  with  several  nuclei  were  to  be  found.  The 
foci,  mentioned  above,  were  sharply  demarcated  from  the 
surrounding  liver  tissue,  which  appeared  to  be  intact. 

Spleen. — The  structure  was  well  preserved,  the  capsule 
thin.  The  Malpighian  bodies  were  normal  as  to  the  ele- 
ments of  wliich  they  consist.  Cells  with  pycnotic  nuclei 
were  scattered  throughout  the  organ,  and  vesicular  cells 
with  small,  deeply  stained,  excentrically  located  nuclei 
were  present.  Polymorphonuclears  were  found  in  the 
tissue  in  considerable  numbers.  No  localized  necrotic  foci 
could  be  found  in  sections  through  the  spleen. 

Cervical  Glands. — The  blood-vessels  were  considerably 
distended.  A  few  hemorrhages  and  polymorphonuclears 
were  present.  CEdema  of  the  capsules  and  surrounding 
tissue  existed.     Part  of  the  gland  was  necrotic. 

Lungs. — The  blood-vessels  were  distended.  The  alveoli 
contained  homogeneous  masses  and  blood.  There  were 
numerous  subpleural  hemorrhages.  The  bronchi  were  col- 
lapsed, and  contained  mucus. 

Kidneys. — The  cortical  part  showed  subdued  struct- 
ure; the  epithelial  cells  had  an  indefinite  outKne  and  occa- 
sionally showed  vacuolization.  The  medullar  part  was 
better  preserved.  There  were  miliary  subcapsular  hemor- 
rhages. A  few  small  foci  were  scattered  throughout  both 
medullar  and  cortical  parts.  They  consisted  of  round-cell 
infiltration. 

Natural  Plague  Infection  in  a  Cat 

The  experiments  of  the  German  Plague  Commission 
proved  that  cats  showed  considerable  resistance  to  plague 
infection  as  cutaneous  and  subcutaneous  inoculations 
failed  to  infect  them.     According  to  the  Austrian  Com- 


150  PLAGUE 

mission,  cats  develop  submaxillary  buboes  if  fed  on  plague 
material.  They  are  said  by  Albrecht  and  Gohn  ^^  some- 
times to  recover.  Out  of  four  cats  fed  on  plague  material 
two  died  of  plague,  one  showing  submaxiLlary,  the  other 
mesenterial  buboes.  Virulent  plague  bacilli  were  found 
in  the  discharge  from  the  nose  and  also  in  the  faeces  of 
cats  which  apparently  did  not  become  infected  after  hav- 
ing been  fed  on  plague  material. 

One  case  of  spontaneous  plague  infection  of  a  cat  was 
recorded  by  Thompson  ^^  in  Sydney. 

W.  Hunter,-"-^  in  Hongkong  made  observations  on  cats 
suffering  from  plague  infection.  The  author  also  under- 
took a  few  experiments,  and  arrived  at  the  following 
conclusions : 

1.  Cats  suffer  from  plague. 

2.  The  disease  may  be  acute  or  chronic. 

3.  The  type  of  the  disease  is  septicaemic. 

4.  The  animals  may  occasionally  play  a  part  In  the 
dissemination  of  plague. 

5.  In  plague-infected  areas  cats  probably  become  in- 
fected through  rats,  which  they  devour  as  food. 

6.  In  plague-infected  districts  possible  plague  infec- 
tion in  cats  is  of  great  importance  from  a  domestic  point 
of  view. 

On  November  27,  1912,  a  sick  cat  was  brought  to  the 
laboratory  for  examination.  It  was  reported  that  the 
animal  was  found  in  a  warehouse  in  which  dead  rats  had 

^^  Uber  die  Beulenpest  in  Bombay  im  Jahre  1897  (189?), 
II  B,  II  C. 

^-  Report  of  an  outbreak  in  Sydney,  1900.  Referred  to 
in  Kolle  and  Wassermann  (1903),  2,  510. 

"Lancet   (1905),   I,   106i. 


ITS  CONTROL  AND  SUPPRESSION      151 

been  found  some  time  previously.  The  rats  were  not 
examined.  In  the  morning  of  the  30th,  the  cat  was  found 
dead  in  the  cage  where  it  had  been  kept  under  observation. 
The  following  are  the  post-mortem  findings : 

The  animal  was  a  fairly  well-nourished  female. ^^  The 
subcutaneous  tissue,  pericardium,  mediastinum,  and  mesen- 
terium  contained  considerable  amounts  of  fat. 

The  subcutaneous  tissue  of  the  neck  showed  oedema  and 
small  hemorrhages.  The  submaxillary  tissues  were  swol- 
len on  both  sides.  When  the  fascise  and  superficial  muscles 
of  the  neck  were  removed,  enlarged  glands  were  found  on 
both  sides.  These  were  closely  attached  to  the  submaxil- 
lary salivary  glands.  The  surrounding  tissue  was  oedemat- 
ous,  but  no  hemorrhages  were  noticed  in  the  vicinity  of 
the  enlarged  glands.  Upon  section  the  glands  were  found 
to  be  necrotic,  and  upon  pressure  a  thin  purulent  liquid 
escaped.  There  were  no  hemorrhages  within  the  glands. 
Several  enlarged  lymph-nodes,  smaller  in  size,  could  be 
followed  down  the  neck  on  the  left  side.  The  lymph-nodes 
in  the  axillae  as  well  as  in  the  groins  and  peribronchial 
nodes  were  normal.  The  mesenteric  glands  were  slightly 
enlarged  and  reddened. 

The  lungs  were  slightly  collapsed.  A  clear,  sanguin- 
eous, slightly  coagulated  effusion  was  observed  in  both 
pleural  cavities.  The  tissue  of  the  lungs  showed  con- 
siderable oedema  and  hypostasis.  The  bronchi  and 
pharynx  showed  no  changes,  the  mucous  membrane  being 
pale  and  thin. 

^*  The  cat  was  the  mother  of  4  kittens  which  were  about 
3  weeks  old  at  the  time  the  cat  was  delivered  for  examination. 
They  were  kept  under  observation  for  several  weeks,  but 
showed  no  signs  of  plague  infection. 


152  PLAGUE 

The  heart  was  normal. 

The  spleen  was  enlarged,  of  light  red  color,  with  fol- 
licles slightly  prominent. 

The  stomach  contents  was  blackish  in  color ;  there  were 
no  hemorrhages  or  ulcers  in  the  mucosa. 

The  liver  was  somewhat  enlarged.  The  organ  showed 
prominent  structure,  the  centres  of  the  acini  being  red, 
the  periphery  lighter  in  color. 

The  kidneys  were  slightly  enlarged  and  pale.  The 
capsule  peeled  off  easily,  the  vense  stellatse  were  prominent, 
the  surface  smooth;  there  were  no  hemorrhages.  The 
cortex  was  increased  in  breadth  and  was  of  the  same 
color  as  the  surface;  the  pyramids  were  darker  in  color. 
The  organ  was  of  fragile  consistence. 

Suprarenals  were  normal,  as  were  also  intestine  and 
bladder. 

The  histological  findings  were  as  follows : 

Bubo. — The  capsule  of  the  gland  was  oedematous.  The 
whole  gland  as  seen  in  cross  section  had  undergone  necro- 
sis, except  a  few  foci  which  still  showed  cellular  structure. 

Lungs. — The  alveoli  were  filled  with  homogeneous 
masses,  containing  but  few  degenerated  epithelial  cells  and 
leucocytes.  The  blood-vessels  were  dilated,  particularly 
in  the  subpleural  part  of  the  organ.  In  some  places  capil- 
lary mycotic  emboli  with  subsequent  hemorrhage  were 
encountered.  The  large  blood-vessels  and  bronchi  were 
normal. 

Salivary  Glands. — Those  glands  attached  to  the  pri- 
mary bubo  showed  the  normal  structure  of  a  combined 
mucous  and  serous  gland. 

Liver. — There  was  considerable  congestion.  The 
centres  of  the  acini  showed  parenchymatous  and  fatty 
degeneration.     The  cells  on  the  periphery  of  the  acini 


ITS  CONTROL  AND  SUPPRESSION      153 

exhibited  typical  fatty  infiltration.  The  large  blood-ves- 
sels and  small  ducts  were  without  change. 

Kidney. — The  cells  of  the  kidney  showed  various  de- 
grees of  degeneration,  ranging  from  parenchymatous  to 
fatty  infiltration.  There  were  a  few  capillary  hemor- 
rhages and  hyaline  casts  present. 

Suprarenals. — These  showed  slight  degeneration. 

Spleen. — This  organ  showed  congestion,  a  few  hemor- 
rhages, and  bacterial  emboli;  otherwise  normal. 

The  bacteriological  examination  of  the  material  from 
this  cat  gave  the  following  results: 

1.  Smears: 

a.  From  the  buboes  showed  degenerated  leucocytes, 

many  lymphocytes,  and  numerous  bacteria, 
some  of  which  resembled  Bacillus  pestis  in  their 
polar  staining. 

b.  From   the    spleen   showed   numerous    plague-like, 

polar-stained  bacilli.  Round  involution  forms 
were  present. 

2.  Cultures: 

a.  From  the  buboes  were  badly  contaminated  with 
Bacillus  coli  and  Bacillus  pyocyaneus  colonies. 

h.  From  the  spleen :  A  few  scattered  colonies  of  Bacil- 
lus pyocyaneus  developed  on  the  surface  of  the 
agar.  Between  the  large  colonies  a  scanty 
growth  of  dewy  appearance  was  noticed.  Smears 
made  from  this  growth  revealed  plague-like 
bacilli  of  the  cultural  type,  showing  a  few  club- 
shaped  involution  forms.  Subcultures  were 
made  in  order  to  secure  pure  culture.  They 
showed  a  pure  growth  of  Bacillus  pestis  as  in- 
dicated by  the  morphology  of  bacilH  and  shape 
of  the  colonies.  Agglutination  with  plague-im- 
mune serum  was  positive. 


154  PLAGUE 

3.  Inoculation  experiments  {vaccination  method): 

a.  One  guinea-pig  was  inoculated  with  the  material 
from  the  left  bubo,  another  one  with  material 
from  the  right  bubo.  They  died  of  plague  on 
the  tliird  and  fifth  days,  respectively. 
h.  One  guinea-pig  was  inoculated  with  the  material 
from  the  spleen.  It  died  of  plague  on  the  tliird 
day. 

c.  One  guinea-pig  was  inoculated  with  material  from 

the  nostrils  obtained  by  swab.  The  animal  sur- 
vived, showing  no  indication  of  plague. 

d.  One  guinea-pig  was  inoculated  with  material  from 

the  rectum  obtained  by  swab.  It  died  of  plague 
on  the  fifth  day. 

Although  plague  infection  among  cats  is  apparently 
a  rare  occurrence,  the  fact  that  cats  may  contract  the 
disease  in  spite  of  the  high  degree  of  resistance  to  plague 
infection  has  to  be  considered  from  the  hygienic  stand- 
point. 

To  appreciate  the  important  role  which  cats  may  play 
in  the  spreading  of  the  disease  one  need  only  consider  the 
close  contact  of  these  animals  with  rats  on  one  side  and 
human  beings  on  the  other.  It  is  also  a  well-established 
fact  that  not  only  plague-infected  cats,  but  also  those 
which  have  devoured  plague-infected  material  and  re- 
mained apparently  normal,  may  excrete  plague  bacilli 
which  have  retained  their  full  virulence. 

^^OTEs  ON  Plague  in  Hong  Kong  by  Dr. 
RoBERG. — During  the  Hong  Kong  epidemic  of 
plague  which  preceded  and  was  coincident  with  that 


ITSICONTROL  AND  SUPPRESSION      155 

of  Manila,  I  visited  that  city  twice  (December, 
1913,  and  July,  1914),  but  I  did  not  closely  in- 
vestigate the  methods  adopted  and  carried  out  by 
the  authorities  there,  for  the  reason  that  the  Manila 
plan  was  so  much  more  productive  of  results,  as 
shown  by  the  apparent  inability  of  the  Hong  Kong 
officials  to  gain  control  of  the  disease.  However, 
I  received  from  Dr.  David  Roberg,  of  the  Oregon 
State  Board  of  Health,  a  copy  of  a  report  made 
by  him  to  the  Secretary  of  his  State  Board  of 
Health,  following  an  investigation  of  the  Hong 
Kong  epidemic  and  the  methods  there  followed. 
I  have  Dr.  Roberg's  permission  to  use  his  report 
and  it  is  herewith  presented.  It  is  dated  Manila, 
April  16,  1914,  and  is  as  foUows: 

I  have  the  following  notes  to  present  on  the  epidemic 
of  bubonic  plague  in  Hongkong. 

On  April  5th  when  I  arrived  in  Hongkong  the  epi- 
demic was  rapidly  approaching  its  height.  With  its  onset 
in  January  there  were  47  cases,  in  February  42,  and  in 
March  223.  During  the  week  previous  to  April  5th,  there 
were  91  cases ;  during  the  six  days  I  was  in  Hongkong 
they  averaged  15  a  day. 

Judging  from  previous  epidemics  the  present  one  will 
be  exceptionally  severe.  The  season  for  the  occurrence  of 
human  plague  is  from  the  months  of  February  to  July. 


156  PLAGUE 

The  onset  is  gradual ;  in  May  it  reaches  its  maximum  and 
then  declines.  In  the  epidemic  of  1912,  for  the  city  of 
Victoria  the  monthly  rate  showed  the  following,  January  9, 
February  22,  March  61,  April  265,  May  513,  June  346, 
July  105,  August  11,  and  September  1.  Comparing  these 
rates  with  those  of  the  present  year  it  will  be  seen  that 
the  number  for  March  far  exceeds  that  of  two  years 
previous. 

Illustrating  the  season  for  human  plague,  with  its  on- 
set, maximum  and  decline,  are  the  monthly  rates  for  the 
city  of  Kowloon  during  1912,  when  the  following  cases 
occurred:  February  2,  March  12,  April  52,  May  246, 
June  152,  July  39,  August  8,  and  September  3. 

The  season  for  human  cases  is  determined  by  the  con- 
dition of  the  rats.  At  the  close  of  the  season  in  July  the 
rats  die  off  from  plague  in  great  numbers  as  it  is  then  the 
hottest  time  of  the  year.  During  the  months  from  Sep- 
tember to  February  the  rats  increase  in  number  and  in 
susceptibility  to  the  extent  of  being  sufficient  to  again 
infect  human  beings.  Moreover  every  other  year  shows  a 
marked  severity  in  the  epidemics  of  human  bubonic  plague. 
This  is  explained  by  the  fact  that  it  requires  two  years' 
time  for  the  rat  population  to  become  of  sufficient  great- 
ness and  susceptibility  to  cause  a  severe  human  outbreak. 
This  is  shown  by  the  yearly  number  of  cases  since  the  year 
1911.  During  the  years  1911,  1912  and  1913  respec- 
tively, there  were  253,  1847,  and  408  cases.  During  the 
present  year  the  monthly  rate  is  exceeding  that  of  the 
heavy  year  of  1912. 

The  severe  epidemic  in  1912  was  a  result  of  the  influx 
of  50,000  Chinese  refugees  into  Hongkong  during  the 
revolution  in  1911.     The  number  of  rats  in  the  native 


ITS  CONTROL  AND  SUPPRESSION      157 

district  depends  upon  the  available  food  supply,  and  as 
a  result  of  this  human  overcrowding  the  amount  of  waste 
food  so  increased  in  the  houses,  yards  and  streets,  that  the 
over  accumulation  of  garbage  could  not  be  kept  pace  with. 
This  influx  also  brought  in  great  numbers  of  susceptible 
rats. 

The  number  of  rats  killed  off  during  the  epidemic  in 
1912  were  so  great  that  in  1913  they  had  not  recovered 
sufficiently  to  cause  a  severe  outbreak  during  that  year, 
and  as  a  result  of  the  lightness  of  epidemic  in  1913,  they 
are  so  increased  in  number  and  susceptibility  now  that  they 
are   causing   a   very    severe    epidemic   in   human   beings. 

Of  rats  in  Hongkong  they  have  the  Mus  decumanus 
or  drain  rat  and  the  Mus  rattus  or  house  rat.  It  is  note- 
worthy that  the  drain  rat  is  found  plague-infected 
throughout  the  year,  while  the  house  rat  is  found  infected 
only  during  the  period  in  which  the  human  epidemics  occur, 
namely  from  February  to  July.  The  number  of  infected 
rats  a  year  run  parallel  to  the  number  of  monthly  cases. 

The  bulk  of  human  infection  is  due  to  the  spread  of 
house  rats.  Man  also  becomes  infected  by  the  drain  rat 
when  the  drains  are  flooded  by  rain  storms  and  the  rats 
are  driven  into  the  houses. 

What  has  made  plague  permanent  in  Hongkong  is  the 
overcrowding  of  the  native  districts.  Besides  there  is  a 
floating  population  entering  and  leaving  the  native  quar- 
ters, numbering  about  4000  a  day.  The  native  houses 
have  been  built  with  double  floors  and  walls  wliich  harbor 
the  rats.  Where  the  construction  is  of  wood  it  is  pos- 
sible to  remove  the  rat  spaces.  It  has  been  found  since 
the  introduction  of  plague  into  Hongkong  in  1894,  that 
those  districts   containing  the  greatest  number  of  soft 


158  PLAGUE 

brick  houses  with  hollow  walls,  have  shown  the  greatest 
incidence  of  plague.  This  can  not  be  remedied  as  it  would 
involve  the  destruction  of  buildings  on  too  large  a  scale. 

The  Woek  of  the  Sanitaky  Boaed 

The  area  under  the  control  of  the  Board  comprises 
the  Island  of  Hongkong  containing  32  square  miles,  with 
a  sea  frontage  of  13  miles  in  length.  Included  also  is  the 
old  city  of  Kowloon  which  is  situated  one  mile  and  a  third 
across  the  harbor  and  contains  two  and  three-fourths 
square  miles.  The  city  of  Victoria  on  the  northern  shore 
of  the  Island  of  Hongkong  has  a  sea  frontage  of  5  miles, 
contains  about  ten  thousand  domestic  buildings,  of  which 
about  one  thousand  are  non-Chinese. 

The  population  of  Hongkong  is  difficult  to  estimate, 
as  the  floating  population  is  so  great.  In  the  1912  census 
there  were  446,614  Chinese  and  21,163  non-Chinese. 

The  city  of  Victoria  is  divided  into  10  Urban  Health 
Districts  and  old  Kowloon  into  2.  There  is  an  inspector 
in  charge  of  each.  These  districts  are  built  over  an  area 
averaging  from  31  to  140  acres.  The  houses  in  these  dis- 
tricts average  one  thousand  and  the  population  from  8000 
to  33,000.  There  are  four  inspectors  in  charge  of  the 
scavenging  work,  one  for  the  disinfection  stations  in  Vic- 
toria and  old  Kowloon,  one  for  the  cemeteries  and  two 
for  general  duty. 

The  measures  employed  by  the  Sanitary  Board  are 
summarized  as  follows : 

1.  The  exclusion  of  rats  from  all  dwellings  by  means 
of  concreted  ground  surfaces,  the  protection  of  all  drain 


ITS  CONTROL  AND  SUPPRESSION      159 

openings  and  ventilating  openings  by  iron  gratings,  and 
the  prohibition  of  ceilings  and  of  hollow  walls  in  new  build- 
ings and  in  those  existing  buildings  from  which  they  have 
been  removed  by  order. 

2.  The  collection  and  bacteriological  examination  of 
all  dead  rats.  Facilities  for  the  collection  of  rats  in  the 
quarters  are  provided  in  the  shape  of  small  covered  bins 
attached  to  lamp  posts,  telephone  posts,  electric  light 
poles,  etc.  These  bins  contain  a  carbolic  acid  disinfectant, 
and  the  inhabitants  are  invited  to  at  once  put  into  them 
all  rats  found  or  killed  by  them.  There  are  650  of  these 
bins  distributed  throughout  the  city  and  its  suburbs,  and 
each  of  them  is  visited  twice  daily  by  rat  collectors  who 
take  all  rats  found  by  themi  to  the  City  Bacteriologist. 
Each  rat  is  at  once  labelled  with  the  number  of  the  bin 
from  which  it  is  taken,  and  if  subsequently  found  to  be 
plague  infected,  a  special  survey  is  immediately  made  of 
the  block  of  houses  in  that  vicinity.  All  rat-holes  and 
rat  runs  are  filled  up  with  broken  glass  and  cement,  de- 
fective gratings  and  drains  dealt  with,  and  rat  poison 
distributed  free  to  the  occupants.  If  several  plague- 
infected  rats  are  found  in  one  locality,  a  special  house-to- 
house  survey  and  cleansing  of  that  district  is  made. 

3.  The  destruction  of  rats  by  poison,  traps  and  bird- 
lime boards;  special  efforts  in  this  direction  being  made 
just  before  the  onset  of  the  regular  plague  season  which 
is  in  the  months  of  from  March  to  July. 

4*.  The  encouraging  of  the  community  to  keep  cats. 

5.  The  systematic  cleaning  and  washing  out  of  all 
native  dwellings  at  least  once  in  three  months  with  a  flea- 
killing  mixture  made  by  emulsifying  kerosene  in  water. 

6.  An  efiicient  daily  scavenging  of  all  streets  and  lanes 


160  PLAGUE 

and  the  daily  removal  of  refuse  from  the  houses,  coupled 
with  the  provision  of  covered  metal  dust-hins,  to  reduce  as 
far  as  possible  the  amount  of  food  available    for  rats. 

7.  The  disinfection  of  plague-infected  premises  by 
stripping  them  and  washing  them  out  thoroughly  with  a 
kerosene  emulsion.  The  bedding,  clothing,  carpets,  rugs, 
etc.,  are  conveyed  in  a  huge  covered  basket  to  the  disin- 
fecting plant  and  steriHzed  with  superheated  steam.  No 
objection  is  made  to  the  treatment  of  plague  cases  in 
native  hospitals,  and  no  restrictions  are  imposed  in  regard 
to  the  burial  of  those  dead  with  plague  except  the  pro- 
vision of  a  substantial  cofBn. 

8.  Every  effort  is  made  by  means  of  lectures,  ad- 
dresses and  explanations  to  induce  the  native  population 
to  participate  in  the  above  preventive  measures. 

Upon  my  last  visit  to  Hong  Kong,  in  July  last, 
plague  was  abating.  The  South  China  Morning 
Post  of  July  15,  1914,  contained  the  following 
statement : 

Plague  is  gradually  disappearing  from  Hongkong. 
Last  week's  return  shows  that  there  were  26  cases,  of 
which  19  were  fatal.  All  were  Chinese.  The  total  number 
of  cases  for  the  current  year  to  date  is  2093,  with  1939 
deaths  resulting. 

I  regret  that  circumstances  do  not  permit  me 
to  relate  in  detail  the  work  done  and  the  observa- 
tions made  during  the  closing  six  months  of  the 
Manila  epidemic. 


ITS  CONTROL  AND  SUPPRESSION      161 

Up  to  the  day  of  my  departure  from  the  PhiUp- 
pines,  in  July,  1914, 1  remained  in  charge  of  plague 
suppression,  but  the  added  duties  of  administra- 
tion at  San  Lazaro  Hospital  and  the  coincident 
occurrence  of  a  cholera  epidemic  prevented  me  from 
keeping  a  detailed  record  in  such  form  as  to  per- 
mit reproduction  here.  It  will  therefore'  suffice 
to  say  that  the  first  six  months  of  1914  witnessed 
the  passing  of  the  most  threatening  situation  that 
has  confronted  the  city  of  Manila  in  years.  The 
record  of  plague  rats  found  does  not  convey  an 
accurate  idea  of  the  prevalence  of  rat  plague  by 
any  means,  for  the  simple  reason  that,  when  found, 
the  rat  cadavers  were  in  such  condition  as  to  forbid 
bacteriologic  examination;  and  inasmuch  as  the 
bacteriologic  test  of  plague  had  been  used  exclu- 
sively in  determining  rat  plague  up  to  this  time,  it 
seemed  desirable  to  adhere  to  the  original  method. 

In  February  we  found  in  one  of  the  districts, 
in  which  we  undertook  systematic  work  in  conse- 
quence of  a  few  cases  of  human  plague,  a  very 
large  number  of  dead  rats,  in  and  adjacent  to 
houses  which  furnished  human  plague  cases.     In 

one  building  alone  more  than  150  rat  cadavers  were 
11 


162  PLAGUE 

found  during  our  cleaning  and  rat-proofing  opera- 
tions. It  is  this  district  concerning  which  the  letter 
to  the  public  (already  quoted)  was  written. 

The  methods  followed  in  treating  this  new  and 
dangerous  focus  of  infection  did  not  differ  from 
those  practised  during  the  previous  year,  except 
in  the  matter  of  intensity.  Forces  of  the  cleaning 
and  rat-catching  gangs  were  increased  and  the  ut- 
most thoroughness  of  treatment  was  insisted  upon. 
The  results  fully  justified  our  policy  and  demon- 
strated again  how  feasible  it  is  to  fight  plague  suc- 
cessfully if  adequate  authority  be  given. 

During  the  last  year  of  the  epidemic  in  Manila 
it  became  the  rule  for  us  to  expect  our  plague 
workers  to  locate  and  find  the  identical  rat  cadaver 
from  which  the  infected  fleas  bore  the  disease  to 
the  hmnan  victim,  provided  the  spot  upon  the  floor 
where  the  patient's  sleeping  mat  had  been  placed 
was  known.  In  the  better  class  of  houses  the  rat 
(sometimes  more  than  one)  was  found  dead  be- 
neath the  floor,  behind  some  post  casing,  or  in  other 
space  caused  by  double  construction.  Time  and 
again  I  have  directed  the  removal  of  some  panel  of 
woodwork,  some  post  casing,  or  a  board  of  the  floor 


ITS  CONTROL  AND  SUPPRESSION      163 

with  the  full  expectation  (seldom  unrealized)  of 
finding  a  dead  rat  or  a  rat  nest.  These  experiences 
were  positively  uncanny  at  times.  In  the  houses  of 
the  poorer  class,  usually  of  bamboo  and  thatch  con- 
struction, the  finding  of  the  rat  was  less  easy  and 
more  uncertain,  although  the  nest  was  repeatedly 
fomid,  and  as  related  elsewhere  the  dead  rat  itself 
might  be  found  in  a  hollow  bamboo  timber,  or  in 
the  thatch  construction  of  the  wall.  In  a  house  on 
Calle  Echague,  from  which  a  Fihpino  and  his  wife 
were  removed,  dead,  within  a  few  hours  of  each 
other,  several  dead  rats  were  found  in  the  floor 
(the  only  piece  of  double  construction  in  the  whole 
house)  within  four  feet  from  the  spot  where  the 
sleeping  mats  were  placed.  A  rat  hole  led  to  the 
nest  and  through  this  hole  the  fleas  from  the  dead 
rats  found  their  way  to  the  human  victims  sleeping 
on  the  floor  above  the  encased  nest. 

These  instances  could  be  multiplied  many  times, 
but  there  is  no  longer  any  special  reason  to  do  so, 
as  the  rat  and  the  rat-flea  are  so  completely  in- 
criminated as  to  render  these  repetitions  quite  un- 
necessary, however  interesting  they  may  be  to  the 
plague  worker.    The  danger  of  pursuing  these  in- 


164  PLAGUE 

vestigations,  to  the  persons  so  engaged,  must  not 
be  lost  sight  of,  and  exposure  of  such  nests  and  rat 
cadavers  should  invariably  be  preceded  by  thor- 
ough spraying  of  the  place,  and  particularly  of 
the  spot  where  tearing  out  of  double  construction 
is  to  be  done.  I  know  of  no  more  dangerous  em- 
ployment than  this,  both  for  laborer  and  bystander. 


CHAPTER  IV 

ITS  DIAGNOSIS  AND  TREATMENT 

It  was  not  my  original  intention  to  include  the 
subjects  of  diagnosis  and  treatment  in  this  presen- 
tation, except  in  so  far  as  I  have  already  referred 
to  them  in  the  relation  of  my  Manila  experiences 
in  the  preceding  pages.  I  have  decided,  however, 
to  add  a  chapter  upon  Diagnosis  and  Treatment, 
for  the  sake  of  completeness.  No  attempt  will  be 
made  to  present  these  subjects  in  the  orthodox  way. 

Rather,  my  remarks  will  be  confined  to  such 
matter  as  I  believe  to  be  thoroughly  practical  and 
relevant. 

In  my  opinion,  the  day  has  arrived  when  we 
may  properly  exclude  from  such  handbooks  as  this 
one  (intended  for  practical  guidance),  all  such 
methods  of  diagnosis  and  treatment  as  have  failed 
to  meet  the  test  of  actual  experience  through  a 
reasonable  length  of  time.  Twice  in  recent  years,^ 
I  have  described  the  diagnosis  and  treatment  of 

^  Tropical  Medicine  (1907)  and  Hare's  Modern  Treat- 
ment (1911),  vol.  1. 

165 


166  PLAGUE 

plague,  attempting  in  each  case  to  present  a  reason- 
ably full  account  of  the  methods  employed  and 
advocated  by  authorities,  for  theoretic  reasons  and 
from  the  recorded  personal  experiences  of  medical 
men  tliroughout  the  world.  There  comes  a  time, 
however,  when  wheat  and  chaff  must  be  separated 
and  when  methods  which  have  failed,  in  application, 
to  justify  preformed  expectations  must  be  rele- 
gated to  the  department  of  historical  medicine. 

Judging  from  recent  medical  text  books  it  is 
evident  that  medical  writers  are  generally  accept- 
ing this  view  as  the  proper  one.  At  any  rate,  my 
experiences  and  those  of  my  medical  friends  during 
the  Manila  epidemic  of  1912-1914,  have  led  me  to 
discard  as  impracticable,  unproven,  disproven  or 
unpromising,  certain  plans  of  treatment  formerly 
deemed  worthy  of  trial.  I  do  not  refer  to  these 
methods  individually  but  will  content  myself,  in- 
stead, with  reciting  briefly  the  methods  which  I 
believe,  from  personal  experience  and  the  collected 
experience  of  others,  to  be  worthy  of  continuance 
and  of  further  trial. 

Diagnosis. — The  rapid  diagnosis  of  plague  is 
always  of  the  utmost  importance,  both  from  the 
view-point  of  prognosis  and  treatment,  in  the  in- 


ITS  DIAGNOSIS  AND  TREATMENT      167 

dividual  case,  and  from  the  community  view-point 
of  the  recognition  of  the  presence  of  a  dangerous 
communicable  disease,  with  the  resultant  obhgation 
falhng  upon  the  health  authorities. 

The  Biologic  Diagnosis. — Let  us  understand, 
first  and  finally,  that  but  one  diagnosis  is  absolutely 
and  irrefutably  dependable,  viz. :  the  biologic  diag- 
nosis. Herein  I  would  include  not  only  the  recov- 
ery of  the  pest  bacillus  from  the  patient,  but  the 
recovery  and  identification  of  the  organism  from 
inoculated  animals,  infected  from  blood,  tissues, 
secretions  or  cultivated  plague  bacilh  derived  from 
the  human  patient  or  cadaver. 

This  entire  process  involves  a  lapse  of  time  of 
several  days,  and,  while  it  is  indispensable  in  the 
earliest  cases  of  an  epidemic,  and  highly  desirable 
for  the  proper  study  of  aU  cases  of  plague,  it  is 
impracticable  and  unnecessary,  in  communities 
where  plague  is  known  to  exist,  to  carry  out  more 
than  the  first  steps  of  the  biologic  diagnosis,  viz.: 
the  recovery  of  B.  pestis  (morphologic  identifica- 
tion) from  the  patient. 

Necessity  for  Trained  Bacteriologist. — It 
is  evident  that  the  services  of  a  trained  bacteri- 
ologist are  indispensable  in  the  accurate  diagnosis 


168  PLAGUE 

of  plague,  unless  (as  rarely  is  the  case)  the  ob- 
server himself  is  both  clinician  and  bacteriologist. 
Even  in  this  case  it  is  far  better  for  two  persons, 
clinician  and  bacteriologist,  to  work  together.  I 
will  not  discuss  the  technic  of  the  procedures  of 
biologic  diagnosis,  which  is  described  by  Dr.  Schobl 
in  the  preceding  pages.  Except  under  circum- 
stances of  necessity,  the  clinician  should  always 
turn  this  work  over  to  the  bacteriologist. 

Serum  reactions,  when  present,  occur  too  late 
to  be  of  service  in  practical  diagnosis. 

The  necessary  procedm-es  of  the  biologic  diag- 
nosis include  blood-culture,  smear  examination 
(microscopic)  of  aspirated  material  from  the 
oedematous  tissues  surrounding  gland  masses  and 
from  glands  themselves;  examination  of  sputum 
smears  and  of  thick-blood  smears. 

All  should  be  practised  but,  according  to  our 
Manila  experiences,  smear  examinations  of  as- 
pirated material  and  blood  cultures  are  the  most 
reliable  methods,  in  the  hands  of  a  competent  bac- 
teriologist. Attention  is  invited  to  the  reports  of 
Dr.  Otto  Schobl,  already  quoted. 

Bacteriologic  Procedure. — ^Dr.  Schobl  was 
able  to  secure  positive  blood  cultures,  within  24 


ITS  DIAGNOSIS  AND  TREATMENT      169 

hours,  from  all  of  a  long  series  of  cases  of  plague, 
both  bubonic  and  septicasmic.  As  much  blood  as 
it  was  possible  to  secure  was  aspirated  from  super- 
ficial veins  and  introduced  into  the  culture  media 
at  the  bedside,  ten  c.c.  being  secured  whenever  it 
was  possible. 

The  smear  preparations  for  staining  and  cul- 
ture inoculations  upon  slants  were  also  made  at  the 
bedside  from  aspirated  matter  obtained  from 
oedematous  periglandular  tissues  or  from  gland 
puncture,  an  aspirating  syringe  being  used.  The 
drop  or  two  of  fluid  which  can  be  expelled  from 
the  hollow  needle  is  usually  sufficient  for  smears 
and  tube  inoculations. 

Non-biologic  Diagnosis. — I  do  not  contend 
that  other  diagnostic  means  than  biologic  ones 
should  not  be  used  in  plague. 

On  the  contrary,  it  will  inevitably  happen  at 
times  that  resort  must  be  had  to  methods  of  diag- 
nosis which  are  purely  clinical.  When  this  is  the 
case,  treatment,  along  lines  to  be  detailed  presently, 
should  be  instituted  upon  the  establishment  of  a 
presumptive  diagnosis.  This  presumptive  diag- 
nosis may  be  reached  after  due  consideration  of 
physical  signs  and  symptoms.    A  carefully  taken 


170  PLAGUE 

history  of  the  onset  and  course  of  the  disease  will 
be  valuable  but  unfortunately  such  histories  can 
rarely  be  secured.  It  is  far  safer  to  mistakenly 
pronounce  a  case  "  plague  "  and  to  institute  ap- 
propriate treatment,  than  it  is  to  hesitate  in  the 
absence  of  a  perfect  clinical  picture  and  to  permit 
the  golden  moment  for  treatment  to  pass. 

It  must  be  remembered  that  septicsemic,  bu- 
bonic and  pneumonic  plague  are  all  manifestations 
of  systemic  infection  with  B.  pestis;  that  they  are 
all  expressions  of  the  same  disease;  that  they  call 
for  the  same  treatment  and  that  when  the  distinc- 
tive signs  of  bubo  or  pneumonia  appear  the  disease 
is  dangerously  advanced. 

It  should  also  be  reahzed  that  every  case  is, 
almost  from  its  onset,  a  septicsemic  case,  either 
mildly  or  overwhelmingly  so.  Accordingly  the 
treatment  should  invariably  be  the  treatment  of 
septicasmic  plague. 

The  attitude  of  the  diagnostician  should  be  one 
of  suspicion  and  he  should  have  the  courage  to 
carry  out  antiplague  treatment,  practically  upon 
suspicion.  In  this  way  only  can  the  mortality  of 
plague  be  greatl}''  reduced.  It  is  true  of  plague, 
just  as  it  is  true  of  cholera,  that  many  of  the  fatal 


ITS  DIAGNOSIS  AND  TREATMENT      171 

cases  develop  and  become  hopeless  before  the  dis- 
ease is  suspected  or  diagnosticated.  It  is  also  true 
that  many  fatal  cases  of  plague,  in  times  of  epi- 
demic, completely  escape  recognition  during  life, 
the  diagnosis  being  made  in  the  autopsy  room. 

Therefore,  I  lay  great  stress  upon  the  necessity 
for  an  attitude  of  suspicion  on  the  part  of  prac- 
titioners, wherever  even  a  single  case  of  plague 
(human  or  rodent)  is  known  to  have  occurred. 

When  it  becomes  necessary  to  establish  a  pre- 
sumptive diagnosis,  i.e.^  without  resort  to  the  micro- 
scope, the  following  symptoms  and  physical  signs 
will  be  found  to  be  most  significant. 

Symptomatology. — Acuteness  of  onset;  ra- 
pidity of  fever  development ;  rapidity  of  the  devel- 
opment of  mental  dulness  or  cloudiness,  impairment 
of  speech,  delirium,  stupor  or  restlessness;  early 
and  extreme  prostration  (perhaps  more  pronounced 
than  in  any  other  acute  disease)  ;  extreme  tender- 
ness over  involved  gland  masses,  in  the  bubonic 
type  of  plague;  cough,  with  considerable  frothy 
sputum,  soon  becoming  blood-discolored,  in  the 
pneumonic  type  of  plague;  and  early  cardiac 
asthenia  in  all  clinical  types  of  plague,  septicsemic, 
pneumonic  and  bubonic. 


172  PLAGUE 

The  following  diseases  may  be  confounded  with 
plague,  if  symptoms  alone  are  considered:  typhus 
(evcanthematicus) ,  influenza  pneumonia,  broncho- 
pneumonia, severe  malaria,  septicaemia,  acute  toxic 
typhoid,  venereal  bubo,  mumps  and  tonsillitis. 

I  call  attention  again  to  the  fact  that  mild  cases 
of  plague,  septiceemic  and  bubonic,  occur  at  times, 
clinical  pictures  in  such  cases  being  incomplete. 

The  statement  that  the  prognosis  in  all  cases 
of  septicaemic  plague  is  hopeless  is  not  confirmed  by 
my  experience. 

It  should  also  be  remembered  that  primary 
pneumonic  plague  and  secondary  pneumonia  devel- 
oping in  the  course  of  systemic  plague  are  quite 
diiFerent  in  their  significance  and  mortality,  pri- 
mary pneumonic  plague  being  well  nigh  invariably 
fatal. 

Pathologic  Considerations. — Only  the  stu- 
dent of  plague  pathology,  who  has  seen  a  large 
number  of  complete  autopsies,  can  understand  how 
universal  is  the  involvement  of  organs,  glands  and 
tissues  in  systemic  plague  and  how  widespread  is 
the  distribution  of  B.  pestis  throughout  the  body, 
and  he  will  best  understand  how  treatment,  to  be 


ITS  DIAGNOSIS  AND  TREATMENT      173 

in  the  least  effective,  must  be  given  in  the  very 
earliest  hours  of  the  disease. 

Plague  is  an  exquisitely  septic£emic  disease  and 
this  fact  must  never  be  lost  sight  of  by  the  thera- 
peutist, who  must  realize  that  from  the  earliest 
moment  of  infection  all  plague  is  septicsemic  plague. 

Treatment,  Conditions  and  Prognosis. — 
Passing  to  the  subject  of  treatment  let  us,  first  of 
all,  admit  that  even  under  the  most  favorable  and 
approved  conditions  of  treatment  the  mortality  is 
extremely  high.  On  account  of  the  delay  which 
usually  occurs  in  the  recognition  of  plague, — a 
delay  which  in  the  natural  order  of  things  is  and 
must  be  the  rule  rather  than  the  exception,  because 
of  the  rapidity  of  onset  of  the  disease  and  the  fact 
that  it  occurs  much  more  frequently  in  the  lower 
social  classes  than  elsewhere, — ^no  brilliant  results 
are  to  be  expected  from  any  plan  of  treatment. 

The  matter  of  plague  treatment  is  far  from 
being  in  the  same  satisfactory  state  as  the  matter 
of  preventive  control.  I  do  feel,  however,  that 
biologic  treatment  from  the  earliest  possible  mo- 
ment, with  serum,  is  of  the  greatest  promise,  how- 
ever discouraging  the  general  prognosis  may  be 
in  plague. 


174  PLAGUE 

Serum  Treatment. — Recent  writers  agree 
that  there  is  no  treatment  with  curative  value  ex- 
cept that  with  antipest  serum.  To  this  behef  I 
subscribe  assent,  as  I  find  it  entirely  in  accord  with 
my  experience  and  that  of  my  colleagues  in  Manila 
during  1912-1914. 

Holding  this  view,  I  can  see  no  reason  for 
repeating  here  the  details  of  purely  symptomatic 
treatment.  Symptomatic  treatment  has  for  its  ob- 
ject the  securing  of  comfort  and  of  relief  from  suf- 
fering for  the  patient  and  is  highly  proper  in  its 
place,  remembering  always  that  it  is  not  curative 
and  that  if  employed  alone  it  is  worse  than  in- 
adequate. 

Symptomatic  Treatment. — Opiates  (mor- 
phine by  needle)  for  pain,  delirium  and  excitement; 
application  of  ice  bags  and  cold  or  tepid  sponge 
bathing  for  high  temperature ;  stimulants  for  heart 
weakness,  are  all  indicated  and  are  required  in 
nearly  every  case  of  plague. 

As  a  rule  surgery  is  not  called  for  nor  appro- 
priate, except  in  cases  which  develop  secondary  sur- 
gical conditions,  which  conditions  we  need  not  con- 
sider at  this  time. 

Statistical  Studies  in  Mortality. — The  sta- 


ITS  DIAGNOSIS  AND  TREATMENT      175 

tistical  study  of  plague  mortality  from  the  point  of 
view  of  treatment  is  misleading  and  unsatisfactory 
for  reasons  already  given  in  our  discussion  of  treat- 
ment, viz.:  failure  to  secure  early  recognition  and 
early  serum  treatment,  and  the  greater  incidence  of 
plague  in  the  lower  social  classes. 

Few  statistical  compilations  divide  the  cases 
studied  into  moribund  and  non-moribund,  and  in- 
deed such  division,  being  a  matter  of  judgment, 
largely  involves  the  personal  equation  of  the 
observer. 

The  ease  with  which  statistics  may  be  moulded 
to  support  theories,  or  to  break  them  down,  all 
with  perfect  honesty  of  purpose,  is  proverbial. 

To  me,  the  spectacle  of  a  single  case  of  plague, 
apparently  ill  unto  death,  recovering  under  the  ad- 
ministration of  antiplague  serum,  is  more  impres- 
sive than  the  contemplation  of  statistics ;  and  I  have 
seen  more  than  one  such  case  respond  to  serum 
treatment  and  recover. 

So  far  as  it  goes,  however,  the  study  of  statistics 
supports  the  view  that  treatment  with  antiplague 
serum  is  effective. 

I  have  not  at  hand  the  records  of  the  last 


176  PLAGUE 

20  or  more  cases,  but  of  the  fii'st  68  cases  of  plague 
in  the  recent  Manila  epidemic,  32  were  either  found 
dead  or  died  upon  the  same  day  that  they  were 
found. 

If  we  exclude  these  cases  from  consideration 
there  remain  36  cases.  All  of  these  patients  re- 
ceived serum  treatment  and  ten  of  them  recovered. 

It  is  at  once  apparent  that  this  percentage  of 
recoveries  (27  per  cent,  plus)  is  far  more  favorable 
than  the  actual  percentage  of  recovery  in  the  series 
in  which  cases  found  dead  and  moribund  are  con- 
sidered, the  recovery  percentage  here  being  a  little 
more  than  14  per  cent.  It  is  also  quite  fair,  it  seems 
to  me,  to  make  this  separation  of  cases,  or  even  a 
more  liberal  one,  if  we  are  to  consider  the  effects  of 
serum  treatment  statistically. 

Dosage  and  Technique  of  Serum  Adminis- 
TEATiON. — The  amount  of  antiplague  serum  to  be 
given  will  vary  somewhat  with  the  age  and  weight 
of  the  patient  and  with  the  apparent  severity  of 
the  case. 

In  general  terms  it  may  be  said  that  adults 
should  be  given  from  300  c.c.  to  500  c.c.  of  serum 
by  injection,  100  c.c.  being  given  every  four  hom-s. 


ITS^DIAGNOSIS  AND  TREATMENT      177 

The  injection  may  be  either  intramuscular  or  in- 
travenous. 

In  view  of  the  improvements  in  technic  of  in- 
travenous administrations  and  its  comparative 
simphcity,  and  especially  in  view  of  the  uncertain- 
ties and  delays  of  absorption  from  the  tissues,  the 
intravenous  route  should  be  given  the  preference. 
The  serum  may  be  delivered  intravenously  from  a 
large  glass  syi'inge,  the  introduction  being  very 
slowly  made,  or  through  a  gravity  apparatus,  as  in 
the  administration  of  salvarsan.  The  serum  should 
not  be  diluted. 

The  use  of  antiplague  serum  for  protective  (im- 
munizing) purposes  is  also  recommended — espe- 
cially when  exposure  to  infection  has  occurred — in 
the  same  way  in  which  diphtheria  antitoxin  is  used. 
Its  protective  properties  are  conceded  to  be  some- 
what superior  to  those  of  plague  vaccines  as  the 
protection  conferred  is  immediate,  whereas  plague 
vaccines  do  not  protect  until  sometime  after  their 
administration.    The  dose  is  from  30  c.c.  to  50  c.c. 

Prophylactic  Serum  and  Anaphylaxis. — 
On  one  occasion  in  Manila  in  1913,  when  some 
30  persons  were  given  prophylactic  doses  of  serum, 
intramuscularly,  following  a  particularly  danger- 

12 


178  PLAGUE 

ous  exposure  to  fleas  from  rats  dead  from  plague, 
there  occurred  a  number  of  cases  of  "  serum  sick- 
ness" (anaphylaxis).  These  persons  suffered 
from  severe  urticarial,  arthralgic  and  nervous 
symptoms,  lasting  for  several  days  and  a  few  were 
obliged  to  enter  a  hospital.  In  one  case  the  symp- 
toms did  not  entirely  abate  for  a  week.  It  has  been 
stated  that  newly-prepared  sermn  is  particularly 
apt  to  produce  serum  sickness  when  used  for  im- 
munizing purposes.  This  form  of  protection  is 
brief  (1  to  2  weeks)  and  is  best  suited  for  use  where 
there  has  been  special  exposure. 

Plague  Vaccines. — ^Haffkine  originally  pro- 
posed prophylactic  immunization,  using  killed  broth 
cultures  of  B,  pestis  ( carbolized  to  %  per  cent. ) ,  giv- 
ing two  injections  at  intervals  of  10  days.  Statis- 
tically it  seems  to  be  shown  that  this  prophylactic 
immunization  with  dead  bacteria  reduces  the  in- 
cidence and  mortality  one-fom'th  or  one-half  (ap- 
proximately). Experimentally,  also,  it  appears 
that  antibodies  (agglutinins)  are  produced  by  the 
vaccine  (and  modifications  thereof).  Instead  of 
broth  cultures,  normal  salt  solution  suspensions  of 
killed  pest  bacilli  are  usually  used  in  vaccines  at 
present. 


ITS  DIAGNOSIS  AND  TREATMENT      179 

Castellani  ^  has  prepared  a  combined  cholera 
and  plague  vaccine  for  use  in  countries  where  both 
diseases  coincidentally  prevail.  It  is  a  mixed 
vaccine,  so  prepared  that  1  c.c.  of  the  emulsion  con- 
tains 1000  millions  of  plague  bacilli  and  2000 
millions  of  cholera  vibrios.  The  cultures  are  grown 
on  agar,  killed  by  phenol  and  suspended  in  normal 
salt  solution. 

He  finds  ( 1 )  that  inoculation  of  the  vaccine  in 
the  lower  animals  induces  a  production  of  pro- 
tective substances  for  the  plague  bacillus  and  the 
cholera  vibrio;  (2)  that  the  inoculation  of  human 
beings  is  harmless  (producing  less  reaction  than 
the  Haffkine  inoculation) ;  (3)  that  a  small  amount 
of  agglutinins,  both  for  plague  and  cholera,  appear 
in  the  blood  of  most  inoculated  persons  (similar  to 
amounts  produced  by  Haffkine's  vaccine),  a  rough 
index  only  of  the  amount  of  immunity  produced. 

^  A,  Castellani:  Journal  of  Ceylon  Branch  of  British 
Medical  Association,  June,  1914. 


INDEX 


Anaphylaxis,  177 
Appearance  of  plague  in  Porto 
Rico,  26 
New  Orleans,  26 
Manila,  26 
Appeal    for   public    cooperation, 

126,  127 
Australia,  plague  in,  22 
Alaska,  plague  in,  22 
Africa,  South,  plague  in,  22 
Africa,  Central,  plague  in,  22 
Africa,  East,  plague  in,  22 
Africa,  British  East,  plague  in, 

25 
Africa,  Portuguese  East,  plague 

in,  26 
Asian    marmot,   28 
Australia,  rat  fleas  of,  32 
Activity  of  fleas,  33 
Attenuation      of     virulence     of 
cholera  organism,  35 
Bacillus  pestis,  35 
Adaptability  of  rat  to  tempera- 
ture and  environment,  61 
Anti-plague  campaign  in  Manila, 

1912-1914,  57 
Amoy,     importation     of    plague 

from,  59 
Anti-rat  measures  in  R.  R.  cars, 

92 
Activity  of  fleas,  98 
Austrian  Plague  Commission,  133 
Agglutination   of   plague   bacilli, 

134-135 


Animals  suspected  of  plague,  ob- 
servations on,  146-149 

Abatement  of  plague  in  Hong 
Kong  in  1914,  160 

Anti-plague  w^ork,  dangers  of, 
163,  164 

Bacteriologic  observations,  127 
Bacillus  pestis,  in  air,  38 
in  ants,  138 
in  bedbugs,  33,  138 
conveyance  by  fleas,  28, 

30,  31 
cultivation  of,  133,  138 
cultural      characteristics 

of,  133,  138 
in  circulating  blood,  133, 

136 
in  cats,  150 
efi'ect     of     temj)erature 

upon,  34 
in  flies,  33,  138 
in  fleas,  138 
in  lice,  33,  138 
eflfect   of    seasonal   con- 
ditions on,  34 
in  cockroaches,  33 
in  sputum,  133 
stability  of  virulence  of, 

35,36 
in  skin,  132 
Blue,  Dr.  Rupert,  31 
Brazil,  plague  in,  22 
Black  Death  of  Europe,  20 
British  East  Africa,  plague  in,  25 

181 


182 


INDEX 


Bite  of  flea,  31 

Brazil,  rat  fleas  of,  32 

Bedbug,  conveyance  of  B.  pestis 
by,  33 

Barber,  Dr.  M.,  38 

Bacterial  \iruses  for  rat  destruc- 
tion, 43 

Bacterial  virus,  Danysz,  53 

Bacillus,  Danysz,  53 

use  of,  in  Odessa,  53 
use  of,  in  Cape  Town,  53 

B.  typhi  murium,   53 

Bacillus,  mouse-typhoid,  of  Loef- 
fler,  53 

B.  enteritidis,  Gartner's,  54 

Bacterial  rat  poisons,  use  of,  in 
Japan,  54 

Beginning    of    Manila    epidemic, 
60 

Binondo,  Manila,  plague  in,  63 

Bamboo  timbers,  closing  ends  of, 
71 

Basements,  insanitary,  73 

Birth-rate  of  rats,  73 

Bionomics  of  fleas,  77 

Batavia,  Dutch  India  (Java),  77 

Bureau  of  Science,  Manila,  93 

Barn  rat,  99 

Burrowing  ability  of  rats,  103 

Breaking   up    rat   nests,   Manila, 
106 

Bacteriologic      examination      of 
plague  patients,  128 

Blood-sucking   insects,    transmis- 
sion of  plague  by,  137 

Bacillus  pestis,  insects  found  to 
contain  (Table  III),  138,  139 

Biologic  diagnosis  of  plague,  167 
procedure,  diagnosis,  168 


Cause  of  plague,  28 

Conveyance  of  plague,  28 

Control  of  plague,  40 

Crowell,  Dr.  B.  C,  14 

China,  plague  in,  21,  22,  24 

California,  plague  in,  22 

Central  Africa,  plague  in,  22 

California  ground  squirrel,  28 

Contact,  plague  through,  29 

Contagious  plague,  29 

Contagion,    India    Plague    Com- 
mission on,  33 

Cockroaches    in    plague    convey- 
ance, 29,  33 

Cats,  plague  in,  29,  76,  149 

Chronic  plague  in  rats,  35 

Chronic  rat  plague,  India  Plague 
Commission   on,   35 

Currie,  Dr.  D.  H.,  31 

Creel,  Dr.  R.  H.,   U.   S.  P.   H. 
Service,  31,  101 

CasteUani,  Dr.  Aldo  (dedication), 
179 

Ceratophyllus  fasciatus,  32 

Cat  fleas,  32 

Ctenocephalus,  33 

Citellus  beecheyi,  38 

Cholera    epidemics,    spontaneous 
abatement  of,  35 
organism,  attenuation  of  viru- 
lence of,  35 

California,  a  plague  centre,  41 

Cost  of  rat  proofing,  49 

Chemical  poisoning   of  rats   and 
ground  squirrels,  54 

Community,  summary  of  preven- 
tion for,  56 

Close  of  year  1912  in  Manila,  67 


INDEX 


183 


Closing  ends  of  bamboo  timbers, 

71 
Cat  plague  case  in  Manila,  76, 149 

fleas,  78 
Correspondence  of  Philippine  and 

Japan  conditions,  83 
Comparative     statistics     in     rat 

catching  methods,   89 
Cresols,  94 
Coloration  of  rats,  99 
Conformation  of  skulls  in  rats, 

101 
Climbing  ability  of  rats,  102 
Collection  and  forwarding  of  rats 

(Manila),  133,  123 
Case   of   Mr.    C.    (Manila),   124, 

125 
Concealing  plague  cases,  94 
Conclusions      concerning      blood 
culture  in  plague  diagnosis, 
136 
from  observations  of  plague 
outbreak     among     experi- 
mental  animals    (Manila), 
146 
Cat,  natural  plague  infection  in, 

149-154 
Conditions,  treatment  and  prog- 
nosis, 173 
Combined  vaccines,  179 

Diagnosis  of  plague,  165 
Definition  of  plague,  28 
Digestive  tract,  infection  through, 

29 
Dog  fleas,  32 
Droplet  infection,  38 
Destruction  of  rats  by  diseases, 

53 


Danysz  bacterial  virus,  53 
bacillus,  53 

use  of,  in  Odessa,  53 
use  of,  in  Cape  Town,  53 

Destruction  of  rats  by  domestic 
animals,  54 

Disinfection  of  ship  cargoes,  56 

Dead,  proper  disposal  of,  56 

Dispersion    of    fleas    from    rat 
cadavers,  Manila,  65 

Death-rate  of  rats,  73 

Dutch  India,  Batavia  (Java),  77 

Duration  of  life  of  fasting  fleas, 
79 

Dead  rats  in  bamboo  house  tim- 
bers, 87 

Disinfection,  theatre,  Manila,  93 

Deception    and    concealment    of 
plague  cases,  94 

Differential  points  in  rats,  unre-^ 
liability  of,  101 

Driving  out  rats  with  formalde- 
hyde gas   (Manila),  106 

Dangers  of  anti-plague  work,  163, 
164 

Diagnosis,  rapid,  of  plague,  im- 
portance of,  166 
biologic,  of  plague,  167 
non-biologic,  169,  170 

Dosage  and  technique  of  serum 
administration,  176,  177 

Extension  of  plague,  19,  22 
Egypt,  plague  in,  20,  22,  25 
East  Africa,  plague  in,  22 
Epidemics,  effect  of  seasonal  con- 
ditions on,  34 
wane  of,  35 
Epidemic  pneumonic  pla^e,  38 


184 


INDEX 


Economic  imtportance  of  rat  de- 
struction, 42 
Estimations  of  loss  by  U.  S.  Agri- 
cultural Department,  42 
Effect   of   superstitions    and  re- 
ligious beliefs  in  India,  43 
of  rat  poisoning  and  trap- 
ping, 73 
Epidemiologic    facts    concerning 

plague  in  Java,  82 
Examination   of    fatal    cases    of 
plague  (Table  I),  130 
of  cases  of  plague  who  re- 
covered  (Table  II),  131 
Experimental  animals,  plague  in, 
139-145 

Flea  conveyance  of  B.  pestis,  30 
Flies,  conveyance  of  B.  pestis  by, 

33 
Fowls,  plague  conveyance  by,  29 
Flea's  stomach,  capacity  of,  31 
bite  and  plague  conveyance, 
31 
Flea  prevalence,  effect  of  seasonal 

conditions  on,  34 
Fox,  Dr.  Carrol,  31,  70 
Fleas,  dog,  32 
cat,  32 
mice,  32 

ground  squirrel,  32 
activity  of,  33,  98 
Fumigation  of  ships,  46 
Flea   carriers,   objection   to   do- 
mestic cats  and  dogs  as,  65 
Favorable  conditions   for  spread 

of  plague  in  Manila,  61 
First  Manila  cases  in  1912,  62 


Fleas  and  their  habits,  77 
bionomics   of,    77 
rat,  of  Philippines,  78 
of  Australia,  78 
of  Italy,  78 
cat,  78 

per  rat,  variations  in  num- 
ber of  (Java),  78 
Flea  larvae,  effect  of  temperature 
and  humidity  on,  79 
imago,  effect  of  temperature 
and  humidity  on,  79 
Fasting  fleas,  duration  of  life  of, 

79 
Flea    prevalence,    prediction    of 
plague  extension  from,  80 
natural  enemies  of,  97 
activity  of,  33,  98 
Field  rat,  99 
Family  Muridge,  99 
Ferocity  of  Mus  decumanus,  109 
Feasibility  of  fighting  plague  suc- 
cessfully, 162 
of  Manila  policy  of  plague 
control,  162 

Great  plague  of  London,  21 
Great  Britain,  plague  in,  22 
Ground  squirrel,  California,  28 
Great  Britain,  rat  fleas  of,  32 
Ground  squirrel,  fleas  of,  32 
Gartner's  B.  enteritidis,  54 
Geographic   grouping   of  plague 

cases  in  Manila,  63 
Ground-floor  sleeping  quarters,  79 
General       cleaning       campaign, 

Manila,  88 
Garbage    cans,    sanitary    orders, 

Manila,  93 


INDEX 


185 


Guinea-pigs  as  indicators  of  in- 
fected liouses,  96 
Genus  Mus,  99 
Gray  rat,  99 
Gunomys  (Nesokia),  100 
Gnawing  ability  of  rats,  103 
German  Plague  Commission,  149 

History   of   plague,    19 
Hawaii,  plague  in,  22 
Hong  Kong,  plague  in,  24,  58,  154 
Heiser,  Dr.  V.  C,  31,  58,  70,  75, 

89 
Hobdy,  Dr.  W.  C,  31 
House  cats  as  rat  catchers,  65 
Half  wild  cats  as  rat  catchers,  55 
Human  plague  in  Tondo  district, 

Manila,  68 
Houses  in  Tondo,  light  material, 

71 
House  disinfection  by  spraying, 

94 
Household  rat  destruction,  plan 

for.  111 

Hong  Kong,  notes  on  plague  in, 

by  Dr.   Roberg,   153,   154, 

155,  156,  157,  158,  159,  160 

the    work    of    the    Sanitary 

Board,  158 
abatemfint  of  plague  in  1914, 
160 
Haflfkine  vaccine,  178,  179 

Introduction,  11 
India,  plague  in,  24 
Indo-China,  plague  in,  24 
Infection  through  digestive  tract, 

29 
Ingestion,  plague,  29 
India,  rat  fleas  of,  3f 


Italy,  rat  fleas  of,  32 
India  Plague  Commission  on  con- 
tagion, 33 
on      chronic      rat 
plague,  36 
Immunity,  plague,  36 
India,  effect  of  superstitions  and 

religious  belief  in,  43 
Isolation  of  sick,  56 
Importation     of     plague     from 

Amoy,  59 
Iloilo,  P.  I.,  plague  in,  70 
Insanitary  basements,  72 
Interpretation   of   the   rat   catch 

and  plague  incidence,  91 
Infected   houses,    guinea-pigs    as 

indicators  of,  96 
India  Plague  Commission,  100 
Insects  found  to  contain  Bacillus 

pestis  (Table  III),  138,  139 
Importance  of  rapid  diagnosis  of 

plague,  166 

Japanese  anti-plague  serum,  18 
Japan,  plague  in,  22,  25 
Java,  plague  in,  25 
Japan,  bacterial  rat  poisons,  use 

of,  in,  54 
Jackson,  Dr.  T.  W.,  correspond- 
ence, 75 
Java,  Batavia,  Dutch  India,  77 
Xenopsylla  cheopis  in,  77 
variations  in  number  of  fleas 

per  rat,  78 
epidemiologic  facts  concern- 
ing plague  in,  82 
Javan  village  house,  84 

"bale  bale,"  rats  in,  86 
Java,  sawah  rat  of,  100 


186 


INDEX 


Jumping  ability  of  rats,  102 
Java,  studies  of  rat  cadavers  in, 
104 

Kerr,  Dr.  J.  W.,  31 
Korn,  Dr.  W.,  U.  S.  P.  H.  Ser- 
vice, 87 
Kerosene  as  an  insecticide,  94 

London,  great  plague  of,  21 

Lantz,  Dr.  D.  E.,  31 

classification  of  rats,  99 

Loemopsylla  cheopis,  32 

Louse,  conveyance  of  B.  pestis 
by,  33 

Loeffler,  mouse-typhoid  bacillus 
of,  53 

Laboratory-proven  plague  rats 
and  others  in  Manila,  61 

Light  material  houses  in  Tondo, 
71 
Manila,  85 

Letter  of  warning  and  appeal, 
125,  126 

Location  of  rat  cadavers  in  re- 
lation to  human  plague  cases, 
Manila,   162,  163 

Mortality,  22,  23,  174,  175 
Menace  of  plague,  28 
Manila,  plague  in,  26 
Manufacture       of       anti-plague 

serum,  18 
Middle  Ages,  plague  in,  20 
Mexico,  plague  in,  22 
Mauritius,  plague  in,  22,  25 
Mediterranean  ports,   plague   in, 

22 
Marmot,  Asian,  28 


Mice,  fleas  of,  32 

Manchuria,  pneumonic  plague  in, 

37 
Methods    of   entry   of    rats   into 

ships  and  cars,  52 
Mouse-typhoid  bacillus   of  Loef- 
fler, 53 
Murium,  B.  typhi,  53 
Manila,  Anti-plague  Campaign  in 
1912-1914  in,  57 
epidemic,  1912-1914,  57 
plague  at  quarantine  in,  58 
importation  of  plague   from 
Hong  Kong  in  1912,  58 
Mariveles  Quarantine  Station,  59 
Manila  epidemic,  beginning  of,  60 
Mortality  and  numbers  of  Manila 

plague  cases,  61 
Manila  cases  in  1912,  first,  62 
geographic       grouping       o  f 

plague  cases  in,   63 
R.  R.  station   focus,  64 
dispersion  of  fleas  from  rat 

cadavers,  65 
close  of  year  1912  in,  67 
Malolos,  P.  I.,  plague  in,  69 
Manila,  taking  charge  of  plague 
suppression  measures  in,  70 
plague   fighting  organization 

in,  71 
rat  plague   in   U.    S.   Army 
Commissary  warehouse,  76 
habitations  and  plague,  83 
light  material  house,  85 
general    cleaning    campaign, 

88 
theatre,  disinfection  in,  93 
Mus  rattus,  99 

alexandrinus,  99 


INDEX 


187 


Mus  decumanus,  99 

ferocity  of,  103 
Manila,  breaking  up  of  rat  nests, 
106 
driving  out  rats  by  formalde- 
hyde gas,  106 
rat  killing  with  dogs,  107 
rat  nests  in  trees,  110 
snakes  in  rat  traps,  111 
rat  swallowed  by  snake.  111 
Multiple    house    infection    (Ma- 
nila), 112-117 
Manila,  collection  and  forwarding 

of  rats,  123,  123 
Mr.  C,  case  of  Manila,  124,  125 
Mamla,  bacteriologic  observation, 
127 
outbreak    of    plague    among 
experimental  animals,  139- 
145 
conclusions  from  observation 
of  plague  outbreak  among 
experimental  animals,  146 
San  Lazaro  Hospital,  13,  69, 

161 
location   of   rat   cadavers   in 
relation  to  human  plague 
cases,  162,  163 
Mortality,    statistical   studies    in, 

22,  174,  175,  176 
McCoy,  Dr.  C.  W.,  31 

New  Orleans,  plague  in,  36 
Natural  enemies  of  the  rat,  43 
National  aid,  necessity  of,  56 
Numbers  and  mortality  of  Manila 

plague  cases,  61 
Nest  materials,  86 
Natural  enemies  of  the  flea,  97 


Norway  rat,  99 
Notes  on  rat  runs,  105 
nests,  105 
food,  105 
Natural    plague    infection    in    a 

cat,   149-154 
Notes  on  plague  in  Hong  Kong 

by  Dr.  Roberg,  153-160 
Non-biologic  diagnosis,  169,  170 

Objection  to  domestic  cats  and 
dogs  as  flea  carriers,  55 

Order  Rodentia,  99 

Outbreak  of  plague  among  ex- 
perimental animals  (Manila), 
139-145 

Observations  of  animals  sus- 
pected of  plague,  146-149 

Plague  conveyance,  28 
in  1910,  24 

conveyance  by  suction  of  in- 
sects, 33 

Porto  Rico,  plague  appears  in, 
26 

Public  cooperation  in  plague  con- 
trol, 126,  127 

Practicability  of  plague  control, 
15 

Philippines,  plague  in,  23 

Peru,  plague  in,  22 

Persia,  plague  in,  25 

Portuguese  East  Africa,  plague 
in,  26 

Public  Health  Service,  U.  S.,  26, 
37 

Pulex  irritans,  32 
paUidus,  32 

Plague  pneumonia,  secondary,  39 


188 


INDEX 


Pneumonic   plague   epidemic,   38 
Prevention  problem,  summary  of, 

37 
Pneumonic  plague,  37 

in  Manchuria,  37 
Plague  inununity,  36 

treatment  and  diagnosis  of, 

165 
control,  4)0 
prevention,  40 
suppression,  40 
campaign  in  San  Francisco, 
41 
Poisons  used  for  rat  destruction, 

43,  44 
Poisonous  gases,  rat  destruction 

by,  45 
Prevention  for  community,  smn- 

mary  of,  56 
Proper  disposal  of  dead,  56 
Philippine    Journal    of    Science, 

58,  70,  128 
Plague  at  quarantine  in  Manila, 
58 
from    Hong    Kong,    Manila, 
>    importation    of,    in   ,1912, 

58 
from  Amoy,  importation  of, 

69 
cases,  numbers  and  mortality 

of  Manila,  61 
rats,   laboratory-proven,  and 

others  in  Manila,  61 
in  Quiapo,  Manila,  63 
in  Binondo,  Manila,  63 
cases  in  Manila,  geographic 

grouping  of,  63 
in  Malolos,  P.  I.,  69 
in  Iloilo,  P.  I.,  70 


Plague  suppressive  measures,  Ma- 
nila, taking  charge  of,  70 
fighting  organization  in  Ma- 
nila, 71 
Population,  removal  of,  in  emer- 
gency, 74 
Plague,  cat,  case  of,  Manila,  29, 
76,  150 
rat,  in  U.  S.  Army  Ck)mmis- 
sary  warehouse,  Manila,  76 
Prediction   of   plague    extension 

from  flea  prevalence,  80 
Plag-ue   prevalence,   seasonal   ex- 
planation of,  81 
in  Java,  epidemiologic  facts 

concerning,  83 
Manila  habitations  and,  83 
Tondo    (Manila)    habitations 

and,  83 
cases,  deception  and  conceal- 
ment of,  94 
commission,  India,  100 
Postmortem      changes,    in     rats 
(Table),  105 
in     rats      (illustration), 

105 
time  of  death  of  rats  as 
indicated  by,  104 
Plan  for  household  rat  destruc- 
tion, 111 
Plague  patients,  bacteriologic  ex- 
amination of,  128 
examination  of  fatal  cases  of 
(Table  I),  130 
of   cases   vi^ho   recovered 
from  (Table  II),  131 
comlmission,   Austrian,    133 
bacilli       from       circulating 
blood,  recovering,  134 


INDEX 


189 


Plague  bacilli,  agglutination  of, 
134,  135 

diagnosis,  conclusions  con- 
cerning blood  culture  in, 
136 

by  blood  sucking  insects, 
transmission  of,  137 

among  experimental  animals, 
outbreak  of  (Manila),  139- 
145 

outbreak  among  experimental 
animals,  conclusions  from 
observations  of  (Manila), 
146 

observations  on  animals  sus- 
pected of,  146-149 

commission,  German,  149 

in  Hong  Kong,  notes  on,  by 
Dr.  Roberg,  153-160 

in  Hong  Kong  in  1914,  abate- 
ment of,  160 

feasibility  of  fighting  suc- 
cessfully, 163 

control,  feasibility  of  Manila 
policy  of,  163 

cases  (human),  location  of 
rat  cadavers  in  relation  to 
(Manila),  163,  163 

importance  of  rapid  diag- 
nosis of,  166 

biologic  diagnosis  of,  167 

a  septicsemic  disease  in  all 
cases,  170 

symptomatology  of,  171 
Pathologic  considerations,  173 
Prognosis,   treatment,   conditions 
and,  173 


Plague,  serum  treatment  of,  174 
symptomatic  treatment,  174 
Prophylactic  serum  and  anaphy- 
laxis, 177 
Plague  vaccines,  178,  179 

Quarantine,  modified,  56 
station,  Mariveles,  59 
Quiapo,  Manila,  plague  in,  63 

Rat  fleas  of  Italy,  33 
of  Brazil,  33 
of  Great  Britain,  33 
of  United  States,  33 
Rats,  chronic  plague  in,  35 
subacute   plague   in,   35 
Requisites  of  the  practical  sani- 
tarian, 13 
Russia,  plague  in,  26 
Rats,  wild,  plague  in,  39 

effect  of  seasonal  conditions 
on,  34 
Rucker,  Dr.  W.  C,  31 
Rosenau,  Dr.  M,  J.,  31 
Rat  fleas,  varieties  of,  33 
of  India,  33 
of  Australia,  33 
Rat  population  of  the  world,  41 
destruction,  economic  impor- 
tance of,  43 
extermination  methods,  43 
natural  enemies  of,  43 
destruction,  bacterial  viruses 
for,  43 
poisons  used  for,  43,  44 
trapping,  44 
traps,  varieties,  45 
destruction      by      poisonous 
gases,  45 


190 


INDEX 


Rats,  starving,  47 
Rat  proofing,  48 

cost  of,  49,  93 
infestation  of  ships,  50 
adaptability  of,  51 
Rats,  methods  of  entry  of,  52 
Rat  destruction  by  rat  diseases, 

53 
Resistance  of  rat  to  diseases  of 

bacterial  causation,  54 
Rats  and  ground  squirrels,  chemi- 
cal poisoning  of,  54 
Rat  destruction  by  domestic  ani- 
mals, 54 
catchers,  house  cats  as,  55 
half  wild  cats  as,  55 
terrier  dogs  as,  55 
on    farms,    terrier    dogs 
as,  55 
Rapid  diagnosis,  importance  of, 

56 
Rat  cadavers,  dispersion  of  fleas 
in  Manila  from,   65 
plague    in    Tondo     district, 

Manila,  68 
proofing  and  rat  destruction, 

inapplicable  at  times,  73 
poisoning,    trapping,    effects 
of,  73 
Rats,  birth-rate  of,  73 
death-rate  of,  73 
Removal  of  population  in  emer- 
gency, 74 
Rat  plague  in  U.  S.  Army  Comr 
missary  warehouse,  Manila, 
76 
fleas  of  Philippines,  78 
of  Australia,  78 


Rat  fleas  of  Italy,  78 

breeding    as    influenced    by 

climate,  81 
in  Javan  "  bale  bale,"  86 
in  thatched  roofs,  86 
dead,  in  bamboo  house  tim- 
bers, 87 
Rat  catch,  variations  in,  88 
Rat  catching  methods,  compara- 
tive statistics  in,  89 
Rat  catch  and  plague  incidence, 

interpretation  of,  91 
Rats,    zoologic    classification    of, 

98 
Rat,  ship,  99 
field,  99 
Rats,  coloration  of,  99 
Rat,  Norway,  99 
gray,  99 
barn,  99 
sewer,  99 
Rats,  unreliability  of  differential 
points  in,  101 
conformation    of    skoHs    in, 

101 
gnawing  abihty  of,  102 
burrowing  ability  of,  102 
climbing  ability  of,  102 
jumping  ability  of,  102 
swimming  ability  of,  102 
Rat  litters,  size  of,  102 
Rats  as  wire  walkers,  103 
as  rope  walkers,  103 
Rat  cadavers  in  Java,  studies  of, 
104 
time  of  death  as  indicated  by 
postmortem     changes     of, 
104 


INDEX 


191 


Rats,     postmortem     changes     in 
(Table),    105 
(illustration),    105 
Rat  runs,  notes  on,  105 
nests,  notes  on,  105 
food,  notes  on,  105 
nests  (Manila),  breaking  up, 
106 
Rats   driven  out  with  formalde- 
hyde gas  (Manila),  106 
Rat  killing  with  dogs    (Manila), 

107 
Rat's  nests  in  trees  (Manila),  110 
Rat  traps,   snakes   in    (Manila), 
111 
swallowed    by    snake 
(Manila),  111 
Rats,   collection  and   forwarding 

of  (Manila),  122,  123 
Recovering    plague    bacilli    from 

circulating  blood,  134 
Roberg,  Dr.  David,  154 

Stability  of  virulence  of  B.  pestis, 

36 
Spread  of  plague  in  recent  years, 

23 
Suppression  of  plague,  40 
San    Lazaro    Hospital,    Manila, 

13,  69,  161 
Schobl,  Dr.  Otto,  14,  29,  30,  76, 

96,  127 
Strong,  Dr.  R.  P.,  16,  36,  38,  59, 

135 
Sixth  century,  plague  in,  20 
South  America,  plague  in,  22,  26 
Siam,  plague  in,  25 
Suez,  plague  in,  2"^ 
South  Africa,  plague  in,  22 


Scotland,  plague  in,  22 

Sumatra,  plague  in,  25 

Straits  Settlements,  plague  in,  25 

Simpson,  Dr.  W.  J. 

Suctorial  parasites  in  plague  con- 
veyance, 33 

Seasonal    conditions,    effect    on 
epidemics  of,  34 
on  rats  of,  34 
on  Bacillus  pestis  of, 

34 
on  flea  prevalence  of, 
34 

Subacute  plague  in  rats,  35 

Spontaneous    abatement    of 
cholera,  35 

Secondary  plague  pneumonia,  39 

Summary    of    prevention    prob- 
lem, 37 

San  Francisco,  plague  campaign 
in,  41 

Ships,  fumigation  of,  46 

Starving  rats,  47 

Ships,  rat  infestation  of,  50 

Summary  of  prevention  for  com- 
munity, 6Q 

Ship  cargoes,  disinfection  of,  6Q 

Sick,  isolation  of,  56 

Steamer,  Loongsang,  69 
Taisang,  59 

Spread     of    plague    in    Manila, 
favorable  conditions  for,  61 

Sleeping  quarters,   ground  floor, 
72 

Swellengreble,  Ph.D.,  N.  H.,  77 

Seasonal  explanations  of  plague 
prevalence,  SI 

Sanitary  orders,  Manila  (garbage 
cans),  93 


192 


INDEX 


Ship  rat,  99 

Sewer  rat,  99 

Sawah  rat  of  Java,  100 

Swimming  ability  of  rats,  102 

Size  of  rat  litters,  103 

Simpson,   surgeon,   U.   S.   P.   H. 

Service,  103 
Studies  of  rat  cadavers  in  Java, 

104 
Snakes  in  rat  traps  (Manila),  111 
Snake,       rat       swallowed       b  y 

(Manila),  111 
Specimen,   sanitary   orders,   116- 

121 
Sanitary    Board    (Hong    Kong), 

the  work  of,  158 
Symptomatology   of  plague,   171 
Serum  treatment  of  plague,  174 
SjTnptomatic       treatment       o  f 

plague,  174 
Statistical    studies    in    mortality, 

174-176 
Serum     administration,     dosage 

and  technique  of,  176,  177 

Types  of  plague,  30 

Treatment  of  plague,  165 

Turkey  in  Asia,  plague  in,  25 

Tarbagan,  28 

Teague,  Dr.  O.,  38 

Terrier  dogs  as  rat  catchers,  55 

Terrier  dogs  as  rat  catchers  on 
farms,    55 

Tondo      district,      Manila,      rat 
plague  in,  68 
human  plague  in,  68 

Taking  charge  of  plague  suppres- 
sive measures,  Manila,   70 

Tondo,  light  material  houses  in, 
71 


Tondo,   Manila,    habitations    and 
plague,  83 

Theatre   disinfection,  Manila,  93 

Time  of  death  of  rat  as  indicated 
by  postmortem  changes,  104 

Transmission  of  plague  by  blood- 
sucking insects,  137 

Trained   bacteriologist,    necessity 
for,  167 

Treatment,  conditions,  and  prog- 
nosis, 173 
serum,  of  plague,  174 
symptomatic,  of  plague,  174 

Technique  and  dosage  of  serum 
administration,  176,  177 

United  States  Public  Health  Ser- 
vice, 26 
rat  fleas  of,  32 

Varieties  of  rat  fleas,  32 

of  rat  traps,   45 
Variations  in  number  of  fleas  per 

rat    (Java),   78 
Van  Loghem,  Dr.  J.  J.,  82,  84 
Variations  in  the  rat  catch,  88 
Vaccines,  plague,  178,  179 
Vaccine,  Haffkine,  178,  179 
Vaccines,  combined,  179 

Widespread  dissemination  in  re- 
cent years,  23 
West  Indies,  plague  in,  29 
Wane  of  epidemics,  15,  35 
Work  of  Sanitary  Board  (Hong 
Kong),  158 

XenopsyUa  cheopis  in  Java,  77 

Zoologic  classification  of  rats,  98 


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